Michael Thompson birdied his final hole on Saturday to grab a share of the lead through three rounds of the Honda Classic.
Thompson began the third round one shot off rookie Luke Guthrie's pace and navigated windy PGA National to an even-par 70.
Playing in the final group, Guthrie and Thompson jostled for position much of the blustery day, with the lead changing hands more than once. The rookie was ahead by one after the Bear Trap, but he couldn't match Thompson's birdie on the par-5 18th and instead settled for par and a third-round 71.
Knotted at 8-under 202 through 54 holes, both Guthrie and Thompson will attempt to secure a maiden PGA Tour victory on Sunday.
"I was confident I would come out here and keep playing my game; just kind of keep plugging along," Guthrie said in a televised interview. "Tomorrow, same thing. I'm proud of the way I handled myself."
Lee Westwood and Geoff Ogilvy turned in matching 70s on Saturday and moved into a tie for third at 6-under, while Rickie Fowler (69) and Charles Howell III (71) ended the third round three shots back of the lead at minus-5.
"I like my chances regardless of the conditions," said Westwood, who recently moved close to PGA National. "I'm playing nicely. Just got a couple of mistakes I made today, but other than that, I'm playing solidly. I have to start making a few putts. I had a lot of chances to make putts that just grazed the hole. I like being out late on a Sunday and having a chance."
World No. 1 and defending champion Rory McIlroy was not on hand to test the tricky conditions after his surprising and sudden withdrawal on Friday.
The 23-year-old walked off the course midway through his second round after carding a pair of bogeys, a double bogey and a triple bogey in his first eight holes, later citing a sore wisdom tooth as the cause.
Tiger Woods remained at even-par with his third consecutive 70 on Saturday. He faced a 9-stroke Sunday deficit at this event last year before turning in his lowest final round on the PGA Tour (62) and finishing runner-up to McIlroy.
The world No. 2 opened with a birdie on Saturday and picked up two more shots before the turn, but he began his inward nine with a bogey and stumbled to a double on the 17th after losing his ball in the high grass near the water's edge.
Fowler had the best finish of the third round, going birdie/eagle, while Y.E. Yang had the day's low score (67), which moved him into a tie with Keegan Bradley (70), Justin Rose (72), Peter Hanson (68) and Graham DeLaet (73) at 4- under.
"The biggest thing is being within a few shots going into the back nine tomorrow," Fowler said. "That's where the tournament really starts."
Guthrie spent 2012 on the Web.com Tour, where he posted a pair of victories and seven top-10 finishes in 10 starts. Now, the 23-year-old is within striking distance of his first PGA Tour win.
Thompson, who tied for second at the U.S. Open last year, quickly pulled even with Guthrie on Saturday courtesy of the rookie's bogey on the second. Both players birdied the next hole, but a bogey by Thompson on the fourth placed Guthrie back in front.
A 2-shot swing followed at the sixth, where Thompson holed out from a greenside bunker for birdie and Guthrie, perhaps still smarting from a missed 4-foot birdie putt on the previous hole, bogeyed and fell from the top spot.
Guthrie atoned at the eighth, getting back to minus-9 with a birdie, and the pair made the turn in a dead heat.
Both players bogeyed the 10th, and while Guthrie closed steady with eight straight pars, Thompson was forced to claw his way to the clubhouse as the wind whipped in the 15-20 mph range.
The 27-year-old dropped another shot on the 11th before bouncing back with a birdie on No. 12. Another bogey on the 16th had Thompson one stroke back, but he played the 18th with precision, nearly rolling home a 20-foot eagle putt before tapping in for birdie and a share of the lead.
NOTES: Westwood has finished in the top 10 at this tournament in two of the last three years ... Guthrie shot a PGA Tour career-best 63 on Friday to grab the lead. His previous best round was 64 in the last round of the 2012 John Deere Classic and in the third round of this season's Humana Challenge ... McIlroy suffered a cut at the Abu Dhabi HSBC Golf Championship and a first- round loss to Shane Lowry at last week's WGC - Accenture Match Play Championship in his only other starts this season ... Last year, McIlroy shot four rounds in the 60s and finished the championship at 12-under 268. That was enough for a 2-shot victory over Woods and Tom Gillis.