Jon Rahm birdied his final two holes to outlast Louis Oosthuizen by one stroke for U.S. Open victory and his first major title.
Oosthuizen was in a three-way share of the lead heading into the deciding round and opened up a one-shot lead on a gripping final day at Torrey Pines.
But Rahm rallied in San Diego, where the emotional Spanish star dramatically birdied the 17th and 18th holes to claim a lead he never relinquished on Sunday.
Rahm signed for a four-under-par 67 to finish six under through 72 holes as 2010 Open Championship winner Oosthuizen (71) settled for a runners-up cheque.
At the scene of his maiden PGA Tour win – the 2017 Farmers Insurance Open – Rahm became the fourth player from Spain to win a major and first at the U.S. Open.
Rahm, who was forced to withdraw from the Memorial Tournament when leading by six shots after testing positive for coronavirus earlier this month, said post-round: "I'm a big believer in karma. After what happened a couple of weeks ago, I stayed really positive, knowing big things were coming.
"I didn't know what it was going to be, but I knew we were coming to a special place, I know I got my breakthrough win here, and it's a very special place for my family. The fact my parents were able to come, I got out of COVID protocol early, I just felt like the stars were aligning.
"I can't even believe I made the first two putts! This was definitely for Seve [Ballesteros]. I know he tried a lot, and wanted to win this one most of all. I just don't know how to explain it! I don't know why, but every time we land here, we are happy. We’re in our spot!"
First Father's Day. First major. pic.twitter.com/ctEKFjnwe9— PGA TOUR (@PGATOUR) June 21, 2021
Oosthuizen was initially circumspect on day four, going one over through eight holes to leave the South African one shot behind defending champion Bryson DeChambeau – who came agonisingly close to a sensational hole-in-one at the par-three eighth.
But DeChambeau was unable to maintain his hot start, finishing with a forgettable six-over-par 77 to end the event eight shots off the pace.
Oosthuizen also failed to keep Rahm at bay – dropped shots at the 11th and 17th holes, paving the way for the red-hot Spanish golfer to emerge triumphant for the first time at a major.
Harris English (68) finished solo third, a stroke better off than Guido Migliozzi (68), two-time U.S. Open winner Brooks Koepka (69) and Collin Morikawa (70) as former world number one Rory McIlroy's final-round 73 resulted in a share of seventh spot at one under.
World number one Dustin Johnson (74) and fellow stars Jordan Spieth (72) Justin Thomas (73), Patrick Reed (67) and Sergio Garcia (68) closed out the event tied for 19th.