James Hahn leaped into contention with a 12-under par 60 on Saturday at the PGA Barbasol championship but fellow American J.T. Poston carded a 66 for a one-stroke lead after three rounds.
Hahn had a putt on 18 for a 59 but couldn't get it to drop, just missing out on a chance to post the 13th sub-60 round in PGA Tour history.
Hahn's 132-yard approach on the par-four 18th spun back, leaving a 35-foot putt that he missed right. Because of wet conditions the players were allowed to use preferred lies.
"Felt like you only get so many opportunities to shoot 59, so I wanted to be aggressive," he said. "Took driver off the tee, didn't make a great swing but ended up in the fairway. I was lucky enough to put my hand on it. Hit a great second shot.
"The balls haven't been spinning back all week and to see it spin back 20 feet was kind of heartbreaking, but I hit a good number, landed right next to the flag and I hit a really good putt. Speed was perfect, just didn't give it enough break."
Poston shot his second consecutive bogey-free 66 to reach 19-under 197 for 54 holes at the Keene Trace Golf Club in Kentucky. He won the 2019 Wyndham Championship for his lone title.
Hahn shared third with Joseph Bramlett at 17-under, two adrift of Poston and one behind second-place American Luke List.
The tournament was delayed twice because of bad weather as the leaders didn't tee off until 5 p.m. local time.
Hahn shot 69 in the first round and 70 in the second. He had four birdies on the front nine Saturday plus an eagle at the par-5 fifth then made four more birdies and another eagle, at the par-5 15th, on the back.
Hahn has only made nine cuts in 21 starts this season.
David Lingmerth (65) and Ireland's Seamus Power (67) were 16-under. Jason Dufner (65) was another stroke back with Derek Ernst (66), David Hearn (67), Bo Hoag (67) and Ryan Armour (69).
Defending champion Jim Herman was 14-under after a 65. He won in 2019, and the event was cancelled last year.