Chris O'Meara/Associated Press

Pressure is supposed to be a key factor in the biggest tournament on the PGA Tour, and it regularly takes its toll on many of the game's most respected players.

However, Si Woo Kim proved that he was oblivious to that element in the final round of the Players Championship at TPC Sawgrass in Ponte Vedra Beach, Florida. The 21-year-old South Korean phenom fired a final-round score of three-under par 69, and that was good enough to earn him a victory in one of the year's most prestigious tournaments.

Kim opened up some distance on the field in the front nine Sunday, and his lead was never challenged throughout the closing holes. As the pressure of playing with the lead mounted, Kim continued to hit shots that honed in on the flagstick like laser beams.

Kim finished the tournament at 10-under par, and that gave him a three-stroke victory over playing partner Louis Oosthuizen and Ian Poulter, who both finished at seven-under.

"I can't believe I'm the winner of this tournament," Kim told NBC interviewer Steve Sands through an interpreter on the network broadcast after winning the tournament. "I can't believe I am the youngest champion of this fifth major."

Kim explained that previous success on the tour kept him from feeling too much pressure. "Usually, I'm very nervous, but I won a tournament last year [Wyndham Championship] and that gave me a two-year exemption. So, I wasn't that nervous this time."

Players Championship Prize Money ($10.5 million purse) Position Player Score Earnings 1 Si Woo Kim -10 $1,890,000 2 Louis Oosthuizen -7 $924,000 2 Ian Poulter -7 $924,000 4 Rafa Cabrera Bello -6 $462,000 4 Kyle Stanley -6 $462,000 6 Brendan Steele -5 $339,937 6 Lucas Glover -5 $339,937 6 Adam Scott -5 $339,937 6 Francesco Molinari -5 $339,937 10 Alex Noren -4 $283,500 PGATour.com; Golf.com

The victory in the Players Championship gives Kim a five-year extension on the tour, and it allowed him to move up to the 21st spot in the FedEx Cup rankings.

J.B. Holmes and Kyle Stanley finished the third round tied for the lead at nine-under par, but both golfers struggled in the final round. Holmes was well out of contention by the time he hit the island green on the 17th, and he found the water twice on that hole.

Holmes collapsed with a 12-over par 84 and finished three-over for the tournament.

Stanley shot a three-over 75 and finished six-under par for the tournament, which left him in a tie for fourth place.

Oosthuizen started the round like he would have a chance to win the tournament when he birdied the second hole, but he could not build on that momentum. He had a double bogey on the fourth hole and a bogey on the ninth.

He tried to get back in contention with an eagle on the 11th, but two bogeys followed before he birdied the 16th hole.

Kim had a superb day with his approach shots and his putter, and he became the youngest Players champion in the history of the tournament. He finished with nine straight pars on the back nine, and he was calm on the outside as he worked his way through the final holes

Kim earned a remarkable payday of $1.89 million for his efforts, and that's the same amount that Jason Day earned for his victory in the tournament in 2016.

Not only did Kim avoid a bogey in the final round, he went the final 20 holes of the tournament without putting an over-par number on his card.

Lynne Sladky/Associated Press

Oosthuizen and Poulter each earned $924,000 for their efforts. Stanley, who rallied over the final holes, finished in a tie for fourth place with Rafa Cabrera Bello at six-under. Those two earned $462,000.

Kim's victory over the field was a tremendous upset from a statistical point of view. He came into the tournament ranked 191st in driving accuracy, 201st in greens in regulation and 200th in scoring average, according to PGATour.com. Despite all those deficiencies, Kim executed to near-perfection in the final round to earn the victory.

Kim became the second South Korean winner of the Players Championship, joining countryman K.J. Choi, who won the tournament in 2011.