Hideki Matsuyama shot 2-under 68 and dropped to sixth at the Wyndham Championship on Saturday, falling six strokes off the pace.
Starting the day in a four-way tie for second, Matsuyama carded five birdies but had one bogey and a double bogey at the par-70 Sedgefield Country Club for a three-round total of 12-under 198. South Korean Kim Si-woo shot a 6-under-par 64 to sit at 18 under and maintain his overnight lead.
Matsuyama had three birdies on the front nine but found a pitfall on the par-4 No. 11, where he missed the fairway with each of his first two shots. He was unable to sink a 36-foot par putt and followed that with a miss from 6 feet.
"I wasn't playing badly through the 10th but I made a big mistake on the 11th," Matsuyama said. "After I missed that bogey putt, my putts got weird."
The 24-year-old also three-putted for a bogey on No. 14 and for a par on No.15, but showed relief as he ended the day well with a birdie on No. 17 and a 4-foot par putt on the 18th.