American debutant Collin Morikawa produced an ice-cool final round to win the British Open by two strokes on a blazing hot afternoon at Royal St George's on Sunday.
The 24-year-old began the day a stroke behind Louis Oosthuizen but played picture-perfect golf in a four-under round of 66 to overhaul the South African and resist resurgent fellow American Jordan Spieth in a three-way battle.
Morikawa barely missed a fairway all day as he made four birdies and dropped no shots, showing incredible composure late on as Spieth applied pressure down the stretch.
He never looked like cracking though and his fourth sub-par round of the week saw him finish on 15-under 265 -- his remarkable consistency born out by the astonishing statistic of only four bogeys all week.
Spieth, who was bidding to win his fourth major and first since the 2017 Open, started his final round badly with two bogeys in his first six holes but an eagle at the seventh launched a gallant chase of Morikawa.
The packed galleries, enjoying a memorable finale after last year's cancellation, roared on Spieth but despite a return to his best, he was unable to catch Morikawa, finishing 13 under, left to rue his bogey-bogey finish the night before.
Oosthuizen ended in a tie for third with Spain's U.S. Open champion Jon Rahm, four shots back after a storming finish.
He led from round one and posted the lowest-ever Open total for 36 holes but wilted and finished with a one-over 71.
Morikawa had the luxury of a two-shot lead as he teed off from the 18th tee before striding down the fairway and two-putting for a victory that never looked in doubt to become the first player to win two majors on debut, having also claimed the 2020 PGA Championship.
"This is by far one of the best moments of my life. Look at all these fans, let's hear it for you guys," Morikawa said after receiving the Claret Jug. To see some of the best crowds I have ever seen I'm looking forward to making my trip every year."
The last debutant to win the Open was American Ben Curtis in 2003, although whereas Curtis was ranked 396th at the time, Morikawa is the world number four.
He only turned pro in 2019 but the University of California graduate has now won two of his first eight majors.
"I've had belief in myself since day one that I turned professional. I do my homework Monday to Wednesday to make sure I know what I need to do," he said.
The finale to a riveting 149th Open was beautifully poised as clear blue skies and light winds provided the perfect conditions for a duel under the sun.
Morikawa collected six successive pars to climb into a share of the lead after Oosthuisen bogeyed the fourth.
Spieth bunkered his tee shot at the par-three sixth and dropped his second shot of the round before an eagle at the seventh flicked the switch.
Morikawa tapped in a birdie at the seventh, but for playing partner Oosthuizen that was where everything went wrong.
His second shot went into a greenside bunker, his third into another bunker, before flying his escape across the green, eventually limiting the damage with a bogey six.
That put Morikawa two shots clear and he turned the screws with birdies at eight and nine to briefly go four clear.
Spieth was not giving up the chase but Morikawa was nerveless, saving par on the 10th with a long putt.
Oosthuizen briefly came alive with a birdie at the 11 after almost holing his tee shot, but Morikawa was relentless.
His poor shots were as rare as trees on the coastal links, and even when he did play one, as he did with his second to the 15th, nothing could knock him out of his stride.
With Spieth just two behind, Morikawa was in trouble in the rough next to the downward sloping green, but the Californian made a sensational up-and-down to save par and he kept Spieth at arm's length thereafter.
"I needed a break, and I didn't get it from (Collin)," Spieth said. "I did all I could. So I'm upset because I really felt like I played well enough to win and made a couple of really dumb mistakes that possibly, if I had maybe played the week before, wouldn't have made."
American four-time major winner Brooks Koepka carded the day's joint best score, a 65 taking him to a tie for fifth while his arch-rival Bryson DeChambeau ended an eventful week with a 65 also, although he was never in contention.
Shane Lowry's admirable defence of the trophy he won in 2019 saw him finish in a tie for 12th after a final round 69.