Rickie Fowler found a water hazard with his drive at the final hole to hand fellow American Beau Hossler the halfway lead at the Houston Open in Texas on Friday.
Fowler's bogey at the par-four 18th left Hossler alone at 11-under 133 after the leader carded a second-round 68 at the Golf Club of Houston.
Fowler also shot 68 to join a group of four players one stroke back on a leaderboard with only eight strokes separating the 90 players who made the cut.
"I'm in good position and nice to be there," Fowler told reporters. "I know I can clean some stuff up over the next couple of days."
Jordan Spieth, playing his way back into form for next week's Masters, carded 67 to trail by two strokes, while another Masters favourite Justin Rose shot 69 to lurk four back.
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Aaron Baddeley and Greg Chalmers are the pick of the Australians at five-under to sit in a share of 42nd place.
"From where I was three days ago, goal accomplished for the week already. From this point anything else is icing on the cake," Spieth said.
Rose was also pleased.
"My iron play has been a bit sharper and when I have missed a green my short game has been on point," said the Englishman.
"That's what I've most been pleased about heading into next week, how the short game's looking.
"For me (this week is) about getting a bit clearer on my shots, visualising them a bit better, getting a bit more committed to my shots.
Three-times Masters champion Phil Mickelson triple-bogeyed the 18th, hitting two balls into the water to fall six strokes behind.
"I didn't strike it very well but I putted phenomenal to stay in it," Mickelson said. "Today was an off day."
The Houston winner will earn the last spot in the Masters, if not already exempt, and Hossler is among those dreaming of a late ticket to the year's first major.
