China No. 1 Li Haotong, trying to become the second Asian man to win a major title, slid down the leaderboard after shooting a three-over 73 in Saturday's third round of the PGA Championship.
Li finished with just two birdies after a sizzling second round that saw him fire a bogey-free 65 to take a two-shot lead through 36 holes at TPC Harding Park in San Francisco.
Li struggled with three bogeys and a double bogey on Saturday, a day after he made history by becoming the first player from China to lead in a major championship.
Li stands at five-under 205 for the tournament, only four strokes back of the leader, American Dustin Johnson, and he could still be a factor in the final round if he can hit more fairways.
Like many players at Harding Park, Li's troubles started with a treacherous stretch on the back nine, making a double bogey on the par-4 13th.
Li never recovered from that stumble and made bogey twice more before the end of his round.
Li, who turned 25 on Monday, is hoping his solid play this week will revive the form that catapulted him to the upper echelons of golf with a third-place finish at the 2017 British Open.
Ranked 114th in the world, Li is hoping four solid rounds of golf in California can vault him back into the top 50 in the world rankings.
Australia's Adam Scott said Li belongs in that elite field.
"He has got all the weapons in the bag," Scott said after Friday's round. "You know, I guess I'd call it erratic, but he has got all the tools... I seem to remember him shooting a great round on a Sunday at a British Open a few years back.
"He has got the arsenal to take it low and play, but we don't see that kind of consistency out of him, and that probably matches his personality a little bit.
"He's young, though, and that's the kind of golf he plays. He plays pretty much all guns blazing, and when it comes off, it's really good."
Li is tied for 13th heading into the final round. His best previous result at a PGA Championship was a 36th last year.
If Li does regroup on Sunday, he could become the second Asian man to win a major, joining South Korea's Yang Yong-eun, who won the 2009 PGA Championship.