Matsuyama takes lead with Schauffele close in Olympic golf tournament
Matsuyama, who missed out on bronze on home soil three years ago in a seven-way playoff, posted a eight under par bogey-free round of 63.
That put the top-ranked Asian player three strokes ahead of the next best clubhouse score so far of five under for Chile's Joaquin Niemann, Argentina's Emiliano Grillo and South Korea's Tom Kim.
Out on the course, however, defending Olympic champion Xander Schauffele of the United States was closing in on the lead at seven under after 14 holes, suggesting he had brought to Paris the form that helped him claim two major titles since May.
US world number one Scottie Scheffler was within touch at four under after completing his first round, which he played alongside Ireland’s world number three Rory McIlroy, who was at three under.
The 60 contenders will all play four rounds at Le Golf National in a stroke play format, with the medallists taking the fewest number of shots to complete the 72 holes.
The skies cleared following an overnight downpour, though stormy conditions are forecast to return later in the day, which could interrupt play.
France's Victor Perez hit the opening tee-shot at 9 am (0700 GMT) to huge applause. He reached the clubhouse at one under, while fellow Frenchman Matthieu Pavon was at one over after 13 holes.
"I was surprised there were a lot of people out here. Victor was in front of me and you could tell how they were cheering for him. It was pretty cool for the first day," Niemann told reporters after his round.
The Paris tournament extends golf's short history at the Games, with the sport having returned to the fold in Rio in 2016 after a century-long absence.
The event organisers are hoping to build on Le Golf National's successful hosting of the Ryder Cup in 2018.
Several players noted during practice this week that the rough appeared less arduous than in 2018, though some players fell foul of obstacles including the water along the first fairway and bunkers by the green on the short second hole.
