SOUTHPORT, ENGLAND - Americans Jordan Spieth and Brooks Koepka tamed a fiendish links course to fire impressive 65s and lead the field by two shots, midway through the British Open first round at Royal Birkdale on Thursday.
Spieth, world No.3 and twice major champion, putted smoothly to pick up five birdies and did not drop a shot after fierce crosswinds buffeted the early starters.
"That was one of my top five rounds at a major," the 23-year-old told reporters. "I'd give myself a nine (out of 10)."
Koepka, who won the U.S. Open last month, hit three successive birdies from the 11th hole before making his only bogey at the 16th. He chipped in from a pot bunker to eagle the par-five 17th and return to the top of the leaderboard.
Thongchai Jaidee was five shots off the pace, still with a good chance of high placement after the first round, shooting even-par 70 with a typical round for The Open - four birdies, two bogies and a double bogey.
Teen sensation Phachara Khongwatmai, however, had three birdies and four bogeys but ran into trouble on the par-4 sixth hole, which he triple-bogied for a 7 and a round of 74, four over par. At the en of the day, he was in 106th place and already threatened with a first-round cut.
There were plenty of golfers behind him. American Mark O'Meara, until recently a major name, was 11 over after the first round, and Phachara's score best many other big names including veterans Sandy Lyle and Stewart Cink on seven over, and David Duval, a stroke behind the Thai teen who will be trying to avoid the cut in his Friday evening round.
Prayad Marksaeng, trying to make the first cut in his sixth Open, was also in deep trouble. He fired a six-over par 76 and was mired in 133rd spot. He will require a huge turnaround Friday night (Thailand time) to survive and play on the weekend.
England's Ian Poulter, runner-up in the 2008 Open on this course, managed four birdies and one bogey in a solid round of 67.
The Ryder Cup specialist, who has never won a major, endured a frustrating 2016 due to injury problems and had to come through qualifying to earn his place in the tournament.
"I've definitely had some low spots in the last 18 months and I was getting very down," the 41-year-old told reporters.
"I'm proud of the way I've been able to get things back on the straight and get back to really focussing hard on what I need to do to get the level of golf back that I think I can play."American Justin Thomas, sporting a black tie, matched Poulter's 67 to finish a shot ahead of world No.2 Hideki Matsuyama of Japan, Sweden's Alex Noren and world No.520 Stuart Manley of Wales.
Defending champion Henrik Stenson of Sweden finished on 69, along with England's Matthew Fitzpatrick and Belgian Thomas Pieters.
Many players struggled in the conditions, however, and American Mark O'Meara endured a day to forget on his return to the course where he won the 1998 Open.
Handed the honour of hitting the first shot of the tournament, O'Meara sent his drive out of bounds before running up a quadruple-bogey eight and he ended up signing for an ugly round of 81.