What held Justin Thomas back in his Olympic debut? His putter … again.

Justin Thomas averages slightly better than four birdies per round on the PGA Tour. In his Olympic debut Thursday, he had none.

The Louisville native scored 18 consecutive pars for a 71 in the first round of the Olympic men’s tournament at Kasumigaseki Country Club’s East Course, which left him eight strokes behind leader Sepp Straka of Austria and tied for 41st in the 60-player field.

“I would love to have some kind of old useless club that I could break over my knee right now,” he said afterward. “But you got to stay patient and trust the process, I guess you could say. But it obviously is annoying when I’m not really seeing the results (from) the work I’m putting in.”

Thomas changed putters prior to the Scottish Open earlier this month, and was rewarded with his only top-10 finish in his last 10 tournaments. But his difficulties on the greens resumed at the British Open and have accompanied him to Japan.

“I never had so many putts, like especially at the Open Championship and again here, where I feel like I’m hitting good putts, feel like it’s good speed and they’re just lipping out instead of lipping in,” he said. “You get on those runs sometimes and it sucks so bad when it’s doing that. But sooner or later, maybe will just take one day and they will fall in for me and I’ll get hot. But it doesn’t feel as far off as it looks.”

Thomas told the Golf Channel the 7,447-yard Olympic course proved easier than he had expected after his practice round, and that the ability of other players to take advantage of the conditions would force him to play more aggressively in the three remaining rounds.

“I knew scores were going to be low,” he said. “I had a lot of chances, but I clearly could not take advantage of them. So I’m going to need to do something pretty special these next three days.”

With rare exceptions, professional golfers compete in the Olympics for the medals and the prestige rather than the prize money. Among those rare exceptions are South Korea’s Sungjae Im and Si Woo Kim, who can earn exemptions from military service by winning medals. But the bonuses paid to American medalists through “Operation Gold” — $37,500 for gold, $22,500 for silver, $15,000 for bronze — compare poorly to what Justin Thomas pays his caddie after a PGA win.

“The good thing about this event versus other events is anything other than first, second and third is irrelevant and that’s really the only mindset I have,” Thomas told the Golf Channel. “I have to go out. I have to be aggressive. I don’t really have a choice. Hitting it in the middle of the greens is not going to do me a lot of good.

“I’m going to have to make a lot of birdies. I know I’m capable of doing it. I’ve don’t it before. I just need to see some of those putts that are lipping out lip in, get on a run and hopefully shoot three really good low rounds here.”