Sung Kang passed his first test on Saturday while chasing his maiden PGA Tour win at the Houston Open.
Rickie Fowler was moving up the leaderboard quickly in the third round, jumping to eight under for the day to tie Kang.
But Kang held steady while Fowler collapsed down the stretch for the second straight day.
Fowler, who started his round at nine under, reached 17 under with two holes to play Saturday.
He tripped up coming home, however, by bogeying the par-four 17th hole, then double-bogeying the 18th after struggling on the green.
Fowler will head into the final round at 14 under, three shots behind Kang, after shooting a five-under 67.
After tying the course record Friday, and breaking the 36-hole tournament record, Kang found birdies a little tougher to produce in round three.
Still, after shooting a one-under 71, he heads into the final round at 17 under.
Russell Henley heads into the final round in third at 13 under. The American finished his day with two straight birdies to get back into contention.
Luke List fired a brilliant seven-under 65 to get to 12 under. He had eight birdies and one bogey Saturday.
The leaderboard is a bit spaced out behind List.
A trio of players (Kyle Stanley, Daniel Berger and Rafael Campos) head into the final round tied for fifth at eight under, with Aaron Baddeley and Hudson Swafford at seven under.