Rain delays, caddie changes, a bad tee shot at a critical moment. Nothing was going to keep Bryson DeChambeau from joining some of golf’s most elite company on Sunday.

In winning the 115th U.S. Amateur at Olympia Fields Country Club DeChambeau joined Jack Nicklaus (1961), Phil Mickelson (1990), Tiger Woods (1996) and Ryan Moore (2004) as the only players to win the NCAA Championship and the U.S. Amateur in the same year.

The whole week was never much of a contest. Both finalists, DeChambeau and Derek Bard, get berths in next year’s Masters, U.S. Open and British Open, but there were few other similarities in their status after Sunday’s match.

DeChambeau never played beyond the 16th hole in his first five matches and had even less trouble with Bard in the 36-hole final, winning 7 and 6 with a torrid nine holes immediately after the lunch break. That’s one of the widest victory margins since the tourney was inaugurated in 1895.

“I kept putting the pedal to the metal,’’ said DeChambeau. “I wanted to play Bryson golf, and that’s what I did. I just made everything.’’

A physics major at Southern Methodist University who lives in Clovis, Calif., DeChambeau, 21, opened birdie-birdie to go 2-up quickly, but that lead didn’t last. Bard, a 20-year old junior at the University of Virginia, won four of five holes in one stretch to go 2-up, but DeChambeau took charge for good after chipping in to win No. 8.

The 47-minute rain delay didn’t help, but he battled back to get to all square and then won Nos. 14, 15 and 16 to claim the lead for good. There were some moments of adversity, though.

During the 42-minute lunch break DeChambeau’s regular caddie, Mike Sly, told him that he couldn’t continue on the bag in the afternoon. A case of plantar fasciitis was too painful. No problem. DeChambeau called on a friend who had carried his bag occasionally in the past and only briefly lost momentum.

His first tee shot of the afternoon round sailed left into the woods, and he was lucky to find his ball. Still, no real problem. Bard, who had won No. 18 to conclude the morning round, took advantage of DeChambeau’s rare muff to win that hole, too. Still, DeChambeau wasn’t ruffled.

He went on a tear, stringing one great iron shot after another and backing up those approaches with brilliant putting. He had Bard dormie after winning No. 10 and closed out the match when Bard’s birdie putt lipped out on the 30th hole.

It wasn’t just the dominating result that set DeChambeau apart from the field during the week. It was also his unconventional style. His trademark is a cap like the one Ben Hogan wore. He also spoke proudly of going to the same college as the late, great Payne Stewart, who also wore similar headgear.

DeChambeau’s clubs are also unusual. The shafts are all the same length, that of a standard 6-iron. His style for lining up putts is different, too. He lines them up with his putter in a horizontal position rather than the usual vertical method – like taking aim with a gun. And, his training methods include cursive writing backwards with his left hand (he’s right-handed) because it improves the sensitivity in his hands.

“Obviously he’s a very smart kid,’’ sad Bard. “I was prepared for all that. Whatever works –and this week it worked for him pretty well.’’

DeChambeau talked during the week of “revolutionizing’’ the game – eventually, of course. He plans to stay amateur for a while to take advantage of the perks of being the U.S. Amateur champion. He’s already on the U.S. Walker Cup team and invitations to a wide variety of big events are in the offing.

“Some people think I’m too technical and analytical,’’ said DeChambeau, “but I’m also an artist. At times I was a little frustrated, but I also was determined. I knew my game was good enough to win this tournament.’’

Only four golfers have won the NCAA individual title and the U.S. Amateur in the same year, and three of those are household names.

Bryson DeChambeau can join the select group – one that includes Jack Nicklaus, Phil Mickelson, Tiger Woods and Ryan Moore — with a victory on Sunday at Olympia Fields Country Club. Moore was the last to pull off the NCAA-U.S. Am sweep in 2004.

DeChambeau, 21, won the NCAA title in April while playing for Southern Methodist. He’ll need to beat Derek Bard, a University of Virginia junior, to complete his sweep of the two big amateur titles.

“I’m the underdog,’’ declared Bard. “Bryson’s had an incredible career and he’s very smart – physics is his major. It’s going to be tough, and I’ll have to play my best to have a chance.’’

Bard might be selling himself short or exercising some gamesmanship. He knocked off Spain’s Jon Rahm, the No. 1-ranked played in the World Amateur Golf Ranking, in Friday’s quarterfinals and has two big wins earlier in the last calendar year – the U.S. Collegiate during the school year and the Sunnehanna Amateur this summer.

Like DeChambeau, Bard had no trouble surviving his semifinal match on Saturday. Japan’s Kenta Konishi went down 3 and 2 against Bard while Sean Crocker, a University of Southern California golfer, was a 4 and 3 loser to fellow California native DeChambeau. DeChambeau is No. 7 in the World Amateur Golf Ranking and Bard No. 51.

DeChambeau, who didn’t play beyond the 16th hole in his five matches this week, isn’t thinking about joining the ranks of Nicklaus, Woods and Mickelson just yet.

“That’d be incredible, I’d be so honored, but I haven’t thought about it yet,’’ he said. “I’m just looking forward to the challenge. In a 36-hole match anything can happen. I will do my best, and I think my best will be good enough.’’

DeChambeau, from Clovis, Calif., is – by his own admission — “unique.’’ All his irons are the length of a standard 6-iron.

“It’s an odd-ball way of playing golf, but it works for me and I think that down the road that could be very beneficial for people starting out.’’

DeChambeau, a right-handed golfer, also trains by writing cursive backwards and left-handed because “it creates more sensitivity with my hands.’’

Both finalists receive exemptions into next year’s U.S. and British Opens and are likely to also be invited to next spring’s Masters tournament.

This 115th U.S. Amateur started with over 7,000 entrants, and 312 survived the nation-wide qualifying rounds to make it to Olympia Fields. The field was reduced to 64 after 36 holes of stroke play competition at Olympia, and all of the matches so far have been over 18 holes. The final calls for 18 holes starting at 8:30 a.m. and another 18 starting at 1:30 p.m.

This is the first time the U.S. Amateur has been played in the Chicago area since Cog Hill, in Lemont, hosted in 1997. The U.S. Golf Assn. presently has no other of its 13 annual national championship tournaments scheduled in the Chicago area. Olympia Fields, a private club in the South suburbs, is hosting the tournament as part of its Centennial celebration.

The 115th U.S. Amateur started with over 7,000 entries world-wide, and 312 qualified for this week’s finals at Olympia Fields Country Club. Now there are only four players left.

Saturday’s semifinals pit Japan’s Kenta Konishi against Derek Bard, a University of Virginia golfer, and Bryson DeChambeau, the NCAA champions from Southern Methodist, against Sean Crocker, an 18-year old from Westlake Village, Calif.

DeChambeau, 21, from Clovis, Calif., was the most impressive survivor in Friday’s quarterfinals. He knocked out of Ireland’s Paul Dunne 3 and 2. Dunne, 22, was a sensation at last month’s British Open when he became the first amateur since Bobby Jones in 1930 win lead that major championship after 54 holes before finishing in a tie for 30th place.

The season has already been a success for DeChambeau, in that he qualified for the U.S. Open and has already been selected for the U.S. Walker Cup team that will take on the Europeans this fall. He’s also the only player in the top 10 in the World Amateur Golf Rankings to still be alive in the U.S. Amateur. DeChambeau carries at No. 7 ranking.

“I so excited,’’ said DeChambeau. “This is the first time I’ve made the semifinals in a USGA event.’’

To get to Sunday’s 36-hole title match, however, DeChambeau must handle Crocker, a 2-up winner over Austin James of Canada. Crocker, born in Zimbabwe, moved to the United States when he was 6 years old. He attends Southern California and is No. 64 in the world rankings.

Konishi, ranked only 632, is playing in his first USGA championship. Konishi was a 1-up winner over Matthew Perrine, a Baylor University sophomore from Austin, Tex., on Friday.

Biggest upset of the quarterfinals came when Bard eliminated Spain’s Jon Rahm’s, the worlds’ top-ranked amateur, 1-up. Bard came after 3-down after 10 holes to get to the semis.

“The whole time I tried to stay positive and patient,’’ said Bard, who birdied the 11th and 12th holes and pulled even when Rahm, who attends Arizona State, three-putted at No. 16. Bard won No. 17 and they halved the 18th.

It didn’t take long to realize that Thursday wouldn’t be a good day for the Illinois players still competing in the 115th U.S. Amateur at Olympia Fields Country Club.

University of Illinois golfer Alex Burge was in the first match of the day in the Round of 32. He lost 2-up when his opponent, Kyle Mueller of Watkinsville, Ga., closed him out by holing a 60-foot putt with a six-foot break on the last hole.

Thomas Detry, Burge’s Illini teammate, was in the second match and Japan’s Kenta Konishi eliminated him in a battle that went 19 holes. David Cooke, the Illinois Open champion from Bolingbrook, also was locked in a tense match with David Oraee of Greeley, Colo, but Greeley came away with a 2-up victory.

That left Bloomington’s Todd Mitchell as the only Illinois hope. Once a shortstop in the New York Yankees minor league system, Mitchell survived the Round of 32 easily by beating 19-year old Australian Ryan Ruffels 3 and 2.

Mitchell’s magic ended there. He went down 4 and 3 to Baylor sophomore Matthew Perrine, of Austin, Tex., in the afternoon Round of 16 matches.

Mitchell, the last player to win the Illinois State Amateur in back-to-back years (2002-03) and the runner-up in the 2008 U.S. Mid-Amateur, was one of five mid-amateurs to qualify for match play and – at 37 — the oldest player to reach the Round of 16. He did it in his seventh U.S. Amateur appearance. This was the third time he qualified for match play; he was a first-round loser the first two times.

“The only reason I tried to qualify this year was because the tournament was at Olympia Fields,’’ said Mitchell. “Making the Sweet 16 here is the perfect place for this to happen.’’

That was some consolation for Mitchell, despite going out with a onesided loss.

“I played so poorly. I’m disappointed that I was unable to bring anything to the table,’’ said Mitchell. “I’m pretty beat up physically and mentally, but I’m grateful that I lasted this long.’’

The field will be cut from eight to four in Friday’s quarter-final matches. Semifinals are Saturday and the championship match, to be played over 36 holes, is on Sunday.

Illinois coach Mike Small was delighted that four of his players were among the 312 qualifiers for this week’s 115th U.S. Amateur at Olympia Fields Country Club. He was even more happy that two of them, Alex Burge and Thomas Detry, were among the winners in Wednesday’s first round of matches.

Both had to do it under difficult circumstances, too. The stroke play qualifying session couldn’t be completed as scheduled on Tuesday, so the 64 match player qualifiers didn’t know when their matches would begin.

“It was hectic,’’ said Burge. “I knew the first match would start at 9:45 so I got here at about 8:45 and just hung out with Detry and putted a little.’’

At 9:20 he was told he’d be teeing off against Sam Stevens, of Wichita, Kan., at 9:45.

Burge hit seven balls as a warmup, then played even par golf in demolishing Stevens 5 and 4. Detry’s match started 10 minutes later, and he had to work harder before ousting Matt Oshrine of Baltimore 2-up.

There were 12 Illinois players among the starters, four made it to match play and all won their first matches. Todd Mitchell, a two-time Illinois Amateur champion from Bloomington, was a 1-up winner over Josh Munn of New Zealand and David Cooke, the reigning Illinois Open titlist from Bloomington, beat Hank Lebloda, of Winter Springs, FL., 3 and 2.

Both will continue their bid to win the oldest championship in American golf on Thursday while Illini teammates Charlie Danielson and Nick Hardy were eliminated in the stroke play competition.

“I’m proud of all four of them,’’ said Small, an Olympia Fields member who will bring his team to the club for the Fighting Illini Invitational next month. “They all played well this summer.’’

Detry, who is from Belgium, spent his summer competing in Europe. Burge won the Chicago District Amateur after taking a redshirt season at Illinois.

“(Burge) has been with us for three national finals,’’ said Small, “and it was weird to redshirt a senior but a freshman (Hardy) came in and hit him beside the mouth a little and (Burge) needed to get better. Not every kid in college sports takes advantage of a redshirt year, but Alex did.’’

His final collegiate season will start as soon as the U.S. Amateur ends, which could be as late as Sunday if he reaches the 36-hole title match. Detry also hopes for a long run this week.

“This is a marathon,’’ said Detry. “It’s a very long tournament. I’ve got to keep playing my game. Anything can happen.’’

That was evident on Wednesday, when Cameron Young, of Scarborough, N.Y., knocked out defending champion Gunn Yang 3 and 2.

Alex Burge and David Cooke both won big tournaments this summer, and now they’re poised to win something much bigger.

Though it’s not official yet, Burge and Cooke most likely survived the 36-hole stroke play portion of the 115th U.S. Amateur at Olympia Fields Country Club and will be among the 64 qualifiers for the match play portion of the event that begins Wednesday.

Burge, who captured the Chicago District Amateur, and Cooke, the Illinois Open champion, were able to finish their stroke play rounds on Tuesday and both were at 1-over-par 141. With overnight rains delaying the start of play by 90 minutes on Tuesday, 54 of the 312 starters could not complete their rounds. They’ll have to finish on Wednesday morning before the matches can begin.

Both Burge, a University of Illinois golfer from Bloomington, and Cooke, a Bolingbrook resident who plays collegiately at North Carolina State, were looking for a strong showing before joining their college teams.

“Once you get to match play it’s anyone’s game,’’ said Burge, a redshirt senior for the Illini. He has already graduated and is using the year to work on a Master’s degree while completing his athletic eligibility.

“Sitting out last year wasn’t the most fun thing to do,’’ said Burge, “but hopefully it’ll pay off in the future.’’

Regardless of how he does in this week’s matches, Burge Fields next month for the Fighting Illini Invitational, one of the top college tournaments every season. Illinois coach Mike Small is an Olympia member, so Burge benefitted from his knowledge of the course.

“It helps, just be to familiar with the scenery, but it’s playing completely different than it does for our (college) tournament,’’ said Burge.

Cooke had to rally to keep his match play aspirations alive after going 2-over-par on the fourth hole of Olympia’s North Course. He got the birdie he needed with a nine-foot putt at No. 16 and then wrapped up a solid par-70 round with a sand save at No. 18.

“Winning the Illinois Open was a good confidence boost,’’ said Cooke. “It made me feel I’m definitely supposed to be here, but down the stretch there was a completely different feel. I had complete control of my game in the Illinois Open. Here is was a grind.’’

Both the North, site of the 2003 U.S. Open and many other major events, and the South were used in stroke play. All matches will be on the North with the 36-hole championship match on tap for Sunday.

SHEBOYGAN, Wis. – No longer is Jason Day the best golfer without a major championship. The 27-year old Australian had been in the conversation for that dubious honor for several years, but he took himself out of it on Sunday by winning the 97th PGA Championship at Whistling Straits.

Day had this one coming. He endured runner-up finishes in three previous majors – at the Masters and U.S. Open in 2011 and the U.S. Open again in 2013. He also held or shared the 54-hole lead in the last three majors before getting the job done on the rugged, bunker-filled Pete Dye-designed course on the Wisconsin shores of Lake Michigan.

He did it in style, too. Day started Sunday’s round with a two-stroke lead and no player got any closer. He had a four-stroke cushion midway through the back nine and won by three over playing partner Jordan Spieth, who was thwarted in his bid for his third major title of 2015 but did succeed in supplanting Rory McIlroy at the top of the Official World Golf Rankings.

Spieth also reached 54 under par for his play in the four majors, which bettered a record held by Tiger Woods, but that was clearly overshadowed by Day’s dominance. His 67 on Sunday gave him a 20-under-par 268 total for the 72 holes – a record low for a major championship — along with the $1.5 million first prize from the tourney’s $10 million purse.

“He (Day) was sitting there swinging as hard as he could off the tee, and every single drive was right down the middle of the fairway,’’ said Spieth. “Typically in a major you’re looking for somebody in Jason’s position to miss a couple of shots and just feel the nerves of his own. He went about it like a seasoned veteran. I wouldn’t say I was surprised, but I was amazed that he kept pulling driver and kept hitting it in the tight zones. I probably would have hit 3–wood in that scenario just to keep it in play. He proved me wrong.’’

Day, who turned pro in 2006, played the Nationwide Tour in 2007 and earned his PGA Tour for the 2008 season. He’s endured a traumatic 2015 season, winning his first World Golf Championship event, contending at both the U.S. Open despite collapsing in the second round while battling a case of vertigo and winning the Canadian Open after making a strong run in the British.

Sunday’s win clearly represents a career breakthrough for Day, who has lived in Westerville, Ohio, since his marriage to wife Ellie. They are expected their second child in October.

“It was a fantastic day for me, personally, and something I’ll never forget,’’ said Day.

The key point in Sunday’s round came midway through it. Day, who had made a 50-foot birdie putt to open a three-shot lead at No. 7, gave his first – and only, as it turned out – sign of cracking when he chunked a chip shot to the No. 9 green. He recovered to make par with a nine-foot putt, however, and neither Spieth nor South African Branden Grace – his top challengers at the time — could take advantage of that minor lapse.

Spieth made bogey on the hole and Grace, playing one group in front, took a double bogey at No. 10. After that it was Day protecting his lead, mainly from Spieth. who shot 68 in the final round. Grace, who posted a 69, was two strokes behind Spieth in third place.

“There were plenty of times when I got out of it, more so just thinking about the future – especially on the back side,’’ said Day. “I had to pull myself back in and say `It’s not over. You’ve got to keep grinding, keep fighting.’ And once I did that I started hitting the quality shots that I needed.’’

While the year’s four major championships are over, the PGA Tour still has its lucrative FedEx Cup playoffs on the schedule. The four-tournament series includes the BMW Championship next month at Conway Farms in Lake Forest.