July 29 (UPI) -- Austria's Sepp Straka turned in a dominant round on the first day of Olympic golf, firing a bogey-free 8-under-par 63 on Thursday to sit alone atop the leaderboard on a day that saw rain and lightning interrupt play in the afternoon.
The world's 161st-ranked golfer, who played collegiately at the University of Georgia, was an unlikely figure to lead a field that includes a powerhouse American team and major names such as Rory McIlroy and 2021 Master's champion Hideki Matsuyama.
Straka, 28, had missed six of his last seven cuts before heading to Tokyo, where he promptly tied an Olympic record in grabbing the clubhouse lead in the first round of the Games. He equaled a feat by Marcus Frasier of Australia and Matt Kuchar of the United States, who each shot 63 at the 2016 Rio Olympics, where golf made its return after 112 years.
Scores were low across the board, with nearly 50 of the 60 competitors at or below par. Many competitors praised the conditions at Kasumigaseki Golf Club, located some 25 miles northwest of Tokyo.
"The course is in such good shape, the greens are perfect," Straka told NBC reporter Steve Sands after his historic round. "If you just give yourself putts, which you can on this golf course, you can really take advantage of some good greens."
Straka's twin brother and former college teammate, Sam, is on his bag at the 72-hole contest.
"It was a really special moment," Straka said. "I could have never dreamt of playing in an Olympics, especially with my brother caddying."
Thailand's Jazz Janewattananond, ranked 150th in the world, finished on Straka's heels at 7-under par after play resumed from the two-hour delay.
Janewattananond said that his experience with the weather in the region helped prepare him to handle the interruption.
"I grew up playing in Asia -- on the Asian tour and all these tournaments in Asia we had a lot of these waits, so I learned how to play with it a little bit," he told NBC's Sands after his round.
Thomas Pieters of Belgium, who was in the same group as Straka, finished tied for third at 6-under after sinking a long putt for a birdie on the 18th hole.
Pieters, who finished fourth at the Rio Olympics, had an eagle on the 11th hole, holing out from 126 yards away, as part of a stellar back nine in which he shot a 5-under-par 30.
World No. 61 Carlos Ortiz of Mexico also finished at 6-under par.
The United States contingent was led on the day by world No. 5 Xander Schauffele, who finished at 3-under par.
Schauffele, whose maternal grandparents live in Japan, has been to the country over a dozen times and added his praise for the conditions of the course.
"[In Japan] they care so much about making everything perfect and if you add that onto the maintenance and the upkeep of a golf course, it's a pretty good combination," he said.
"Everything is so pristine. If you're sitting in the fairway, your ball is teed up as if you're at home trying to tee it up yourself," he said. "The greens are really nice, so just roll in some putts."
Schauffele's grandparents were unable to watch in person because of the pandemic-driven state of emergency in Tokyo, which has kept spectators away from events.
"Of course I'd love to see my grandparents," Schauffele said. "I know they're watching coverage. If I can Facetime them or talk to them a little later, that would be nice."
Rounding out the American contingent at the Games are No. 3 Collin Morikawa, coming off a title this month at the British Open, No. 4 Justin Thomas and Patrick Reed. Reed was a last-minute replacement for No. 6 Bryson DeChambeau, who tested positive for COVID-19 just ahead of the Games.
Spain's Jon Rahm, the world No. 1, also tested positive for COVID-19 and was forced to withdraw from the Olympics.
Reed finished at 3-under and Morikawa was at 2-under. Justin Thomas struggled with his putting game and finished his round at even-par.
"It was a very frustrating and disappointing day," Thomas said. "I left a lot out there...I drove the ball pretty well and had a lot of chances but I clearly could not take advantage of any of them. I'm going to need to do something pretty special these next three days."
Rory McIlroy, representing Ireland at the Olympics, finished at 2-under.
Japan's Hideki Matsuyama, who is looking to add a gold medal to the green jacket he won at the 2021 Master's, also finished his day at 2-under.