St. Louis, Missouri (Kyodo) -- Japan's Hideki Matsuyama shot a 3-over 73 to fall 12 strokes off the pace at the PGA Championship as American Brooks Koepka claimed the Saturday lead in the year's final major.
Matsuyama, who carded a 1-under 69 in the rain-delayed second round, undid three birdies with four bogeys and a double bogey to fall into an eight-way tie for 63rd place at Bellerive Country Club.
The 26-year-old Japanese, who along with compatriot Yuta Ikeda carded a first-round 68 to open the day four strokes off the pace, bogeyed the first to set the tone for a challenging round.
"I just had a feeling it wasn't going well. I couldn't find the fairway and that made it tough to keep up," Matsuyama said. "I want to be able to play better tomorrow."
Koepka, coming off his second consecutive U.S. Open win, overcame two bogeys with six birdies for a 66 to snare a two-stroke lead over Australia's former world No. 1 and 2013 Masters champion Adam Scott.
"I feel like I know that I was playing good, so I knew I was going to have a pretty good chance (of winning)," said Koepka. "My odds were pretty good this week with the way I hit it last week."
Spain's Jon Rahm, and Americans Rickie Fowler and Friday leader Gary Woodland sit in a tie for third at 9-under, one shot ahead of a star-studded group of six that that contains five major winners in Tiger Woods, Jason Day, Charl Schwartzel, Stewart Cink and Justin Thomas.
Elsewhere for Japan, Satoshi Kodaira managed four birdies but gave back three shots in a five-hole span to finish with a 69, while a lone bogey earned Ikeda a 71. Both Japanese players sit at 2-under and in a 12-way tie for 45th.
"My putting got better," Kodaira said. "I started thinking that I couldn't do any worse than I was, and that seems to be working. I think I'm headed in a good direction."