At simply 24, Morikawa claimed his second main thanks to a bogey-free spherical of 66 to end on 15 underneath par.
The American had by no means even performed in hyperlinks situations till final week’s Scottish Open when he tied for 71st, the worst end of his skilled profession.
But the world quantity 4 confirmed no signal of inexperience as he revelled within the sweltering situations as temperatures hit 30 levels celsius in Sandwich on England’s south-east coast.
Overnight chief Louis Oosthuizen‘s bogey on the fourth allowed Morikawa to transfer right into a share of the lead and he by no means regarded again after a two-shot swing on the par-5 seventh.
A dream debut 👏Congratulations, Collin Morikawa, Champion Golfer of the Year 🏆 #TheOpen https://t.co/x1TfIPewYI
— The Open (@TheOpen) 1626629598000
Oosthuizen, who completed at 11 underneath in a share of third with Jon Rahm, twice discovered bunkers across the inexperienced to drop one other shot.
Meanwhile, Morikawa drained the primary of three consecutive birdie putts to hit the flip at 14 underneath.
The 2020 US PGA champion wanted his putter to keep sizzling on the again 9 simply to save par at 10, 11 and crucially at 15 with Spieth respiratory down his neck.
But by that point, he had moved to 15 underneath with one other lengthy-vary putt on the par-5 14th.
Three stable pars coming hand-crafted Morikawa the primary British Open debutant to win since Ben Curtis’ shock success additionally at Royal St. George’s 18 years in the past.
Spieth was left to remorse his sloppy end to Saturday’s third spherical when bogeys on the last two holes noticed him begin the day two behind Morikawa.
The 2017 British Open champion slipped again to seven underneath after dropping one other two photographs on the fourth and sixth earlier than roaring again in a fashion that implies he won’t be ready lengthy to add to his three majors.
An eagle on the seventh launched Spieth’s problem and he accomplished the ultimate 12 holes in six underneath par with additional birdies on the ninth, tenth, thirteenth and 14th to put the stress on Morikawa.
But Morikawa by no means flinched to change into the primary man to win two majors on debut at that occasion.
Rahm additionally confirmed why he was the pre-event favorite after touchdown his first main ultimately month’s US Open with a superb 66 that would have been much better however for a greater day with the putter.
The Spaniard wanted an eagle on seventh to get him going, however simply ran out of holes after 4 consecutive birdies between 13 and 16.
Oosthuizen’s look forward to a second main goes on as he completed within the prime three for the eighth time since his sole success within the 2010 British Open at St Andrews.
The pristine situations provided the possibility for one of the chasing pack to launch themselves into rivalry.
Four-time main champion Brooks Koepka made a late cost for his first British Open with a 5 underneath par spherical of 65 to get to eight underneath, however was left to rue his two over par rating on Saturday.
“I didn’t play good enough Saturday,” stated Koepka. “Doesn’t really matter what I finished today. I didn’t have a chance to win and that’s disappointing.”
South African Dylan Frittelli, who was solely known as into the sphere as eleventh reserve on Monday, completed fifth on 9 underneath.
World primary Dustin Johnson completed in a tie for eighth on seven underneath.