Hideki Matsuyama shot 4-under 66 on Thursday to tie for eighth after the first round of the Wyndham Championship, but found himself thinking about the Tokyo 2020 Olympics.

Returning from a two-week break, Matsuyama carded five birdies and one bogey at the par-70 Sedgefield Country Club and sits three strokes behind leaders Rafa Cabrera Bello of Spain and American Kevin Na. The event is the final regular season tournament on the U.S. PGA Tour.

"It's a positive that I finished with a decent score," said Matsuyama, who pulled out of the Rio Games with concerns over the Zika virus and rested in Japan before tuning up at his base in Florida.

While Briton Justin Rose claimed the gold medal in Brazil with a two-shot victory over Sweden's Henrik Stenson, Matsuyama gained some motivation for the 2020 Games after watching his compatriots ascend medal podiums in other sports.

"I just watched the final hole," Matsuyama said. "I thought they were amazing. But rather than envy, I felt I'd rather concentrate on doing my best looking ahead to Tokyo 2020."

"(Japanese athletes) made me want to get one of those medals too. It's in four years time so it might be a bit early but there are plenty of things to work on before then."