After receiving nearly 4½ inches of rain, enduring three weather delays totaling just more than four hours and competitors playing 36 holes of challenging golf, the 4th U.S. Amateur Four-Ball Championship at Jupiter Hills Club finally is ready for the knockout stages.

The competition now moves exclusively to the longer and more physically demanding Hills Course. All but six Round-of-32 matchups are in place, with the final six spots in the draw being decided in Monday morning’s 7-for-6 playoff on the Village Course.

Virtually all of the high-profile sides have qualified, although defending champions Frankie Capan and Shuai Ming Wong needed to survive the playoff to get into the draw.

Here are five matches to keep an eye on (all times EDT):

Clark Collier/Kyle Hudelson vs. David Denham/Stuart Moore (9 a.m.)

Oklahoma City natives Collier, 28, and Hudelson, 30, were the darlings of last year’s championship, advancing all the way to the championship match at Pinehurst Resort & Country Club’s Course No. 2 after getting into the field as last-minute alternates. Denham, 35, is a former University of Georgia standout who helped the Bulldogs win the 2005 NCAA title. The 2017 Georgia Mid-Amateur champion also qualified for the 2005 U.S. Open at Pinehurst, missing the cut. Like Denham, Moore, 35, is a reinstated amateur who played briefly on the mini-tours after graduating from Auburn University.

Don Carpenter/Keith Guest vs. Chip Brooke/Marc Dull (9:24 a.m.)

This will be a border war between Georgia and Florida. Athens, Ga., residents Carpenter, 47, and Guest, 33, come into the match with some momentum after carding a 6-under 64 on the Village Course in Sunday’s second round of stroke play. Brooke, 42, of Altamonte Springs, Fla., and Dull, 32, of Winter Park, Fla., feel like they have unfinished business after a semifinals run a year ago. Dull, a full-time caddie at Streamsong Resort, also was a runner-up in the U.S. Mid-Amateur three years ago just up the road at John's Island Club in Vero Beach.

Dennis Bull/Andrew Price vs. Richard “Skip” Berkmeyer/Brad Nurski (9:36 a.m.)

This will be a classic battle between Midwesterners with previous USGA experience. Bull, 36, of Norwalk, Iowa, was a quarterfinalist in the 2012 U.S. Mid-Amateur and helped Iowa finish second in the 2012 USGA Men’s State Team Championship. Price, 36, of Lake Bluff, Ill., won the 2016 Chicago District Golf Association Amateur and 2014 Illinois Mid-Amateur. He’s also qualified for seven USGA championships. Nurski, 39, of St. Joseph, Mo., is a long-hitting left-hander who was the runner-up in the 2014 U.S. Mid-Amateur. He’s also a two-time Missouri Amateur and two-time Missouri Mid-Amateur champion. Berkmeyer, 44, of St. Louis, Mo., has qualified for 30-plus USGA championships as well as winning three Missouri Amateur and three Missouri Mid-Amateur titles.

Zach Burry/Trent Wallace vs. Frankie Capan/Shuai Ming Wong (10:36 a.m.)

The No. 2 seeds, fresh off a pair of 65s in stroke play, draw the defending champions in what should be an intriguing match. Capan, 18, of North Oaks, Minn., and Wong, 18, of Hong Kong China, survived the 7-for-6 playoff on Monday morning by making a par on the first hole of the Village Course. Capan, headed to the University of Alabama this fall, was the runner-up in the prestigious Sage Valley Junior Invitational last month. Wong, who will begin playing for Southern Methodist University in the fall, captured last year’s Junior Players Championship up the Florida coast at TPC Sawgrass in Ponte Vedra Beach. Last year, Wallace, 20, of Joliet, Ill., became the first Illinois State University golfer in 42 years to qualify for the NCAA Championships. He is entering his senior season, while Burry, 22, of Quincy, Ill., just graduated from the school.

Hayes Brown/Jack Larkin vs. Darin Goldstein/Trevor Randolph (11:12 a.m.)

Larkin, 56, of Atlanta, Ga., is seeking his second USGA championship in the last 40 years after claiming the 1979 U.S. Junior Amateur title at Moss Creek in South Carolina. His partner is 28 years his junior, but the son of his best friend, Mike Brown. It was Hayes Brown, a Wofford graduate who lives in Charlotte, N.C., who contacted Larkin about trying to qualify for the U.S. Amateur Four-Ball because Larkin’s son, Jack Jr., had a scheduling conflict. He just completed his junior season on the University of Georgia golf team. Randolph, 45, of Franklin Lakes, N.J., qualified for the inaugural U.S. Amateur Four-Ball with a different partner (lost in Round of 32). Goldstein, 36, of New York, N.Y., is a two-time Long Island Amateur champion who is competing in his fourth USGA championship.

David Shefter is a senior staff writer for the USGA. Email him at dshefter@usga.org.