Sweden's Daniel Chopra opened up a two-stroke lead after the third round of the Buick Open following a four-under-par 68.
Chopra sunk a 15-foot birdie on the 18th hole to move onto 16-under 200 overall, two clear of Dudley Hart, Woody Austin and Bubba Watson.
The 34-year-old Swede played his opening nine holes in two under and had a one-stroke lead over Hart.
Chopra then started his back nine with a birdie and closed it with another while Hart bogeyed the last to drop into a tie for second.
Chopra said: "Today I was fairly surprised that the scores did not kind of run away; being two behind and being behind Bo Van Pelt, I was pretty sure that pretty close to 20-under was going to be leading by the end of the day.
"I got up to 16 and that kept me with a two-shot lead; I don't know how. I can't explain it.
"Maybe the rain overnight softened up the fairways and the course wasn't playing as short and the greens were softer."
Two-time PGA Tour winner Chopra started the season with a win at the season-opening Mercedes-Benz Championship, but has struggled since and has only managed a 32nd place at the Sony Open.
He added: "Everybody says it's tough to play with a lead, but we try to get a lead, and two shots is better than one, and three is better than two. So the bigger the lead you've got, the better.
"It just gives that you little bit of a cushion to allow yourself that one extra hole where maybe you should have made a birdie on that you expected to make birdie and if you don't, it gives you that extra one hole of patience.
"That's what I'm going to do out there tomorrow - practice patience all day long."
After a 70 yesterday, his worst round of the tournament, Hart was not willing to venture a guess on a winning score, but he did look forward to setting up more birdie opportunities after making four in the third round against two bogeys.
"It depends on weather; depends on wind. I'm not going to really worry about a number," said Hart, who is also searching for his third tour title and first since the 2000 Honda Classic.
"I'm just going to try to follow the shots, and I feel like my putter is working pretty well for the most part. And if I can get myself some more opportunities, I feel confident that I can make some."
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