Will Zalatoris beat Austria's Sepp Straka on the third play-off hole to clinch his maiden PGA Tour win at the FedEx St Jude Championship in Memphis.
After both finished on 15 under par, they could not be separated until TPC Southwind's par three 11th.
Straka went into the water off the tee, while American Zalatoris' first shot ended on a brick wall above the hazard.
Zalatoris took a drop and pitched to seven feet before sinking a bogey putt as Straka only made the green in four.
"It's kind of hard to say 'about time' when you're in your second year on Tour but (it's) about time," said 25-year-old Zalatoris, who tied for second at this year's US Open and lost a play-off to Justin Thomas at the PGA Championship.
"Considering all the close finishes that I've had this year, to finally pull it off means a lot."
Zalatoris was named PGA Tour rookie of the year after finishing runner-up at the Masters in 2021.
He has risen up to 14th in the world rankings after eight top-10 finishes this year.
Earlier, 29-year-old Straka missed a birdie to win the tournament on the 18th as he carded a three-under 67, while Zalatoris made par on the final hole for a round of 66.
The St Jude Championship is the first of three events to decide the Tour champion, with the winner picking up $18m (£14.8m).
Overnight leader JJ Spaun finished on five under, tied for 42nd, after a 78, while Open champion Cameron Smith from Australia ended on nine under following a two-shot penalty before the final round.
Americans Brian Harman and Lucas Glover tied for third on 12 under, while seven players finished on 11 under, including England's Matthew Fitzpatrick and Spain's Jon Rahm.
Smith, who would have leapfrogged American Scottie Scheffler into the world number-one spot with victory, carded a final-round 70.
He was penalised two strokes after being judged to have incorrectly replaced his ball in a penalty drop during his third round.
Forced to take a drop after hitting his tee shot into the water on the par-three fourth, he dropped the ball outside the penalty area and it rolled back, coming to rest touching the red line marking the drop zone.
Smith had carded a three-under 67 on Saturday to move to 11 under par.
Rules committee members reviewed video replays of the hole after Smith had finished his round, before summoning him to discuss their findings.
Gary Young, of the PGA Tour rules staff, said: "At that point, he said 'yes, my ball was definitely touching the line'. He wasn't aware that no portion of the ball could be touching the line."