Phil Mickelson dropped three shots over his final four holes, but was still able to hang on to a share of the lead at the Wells Fargo Championship.
Mickelson tripped to a 1-over 73 during Saturday's third round to finish 54 holes at Quail Hollow at 8-under-par 208.
He was joined atop the leaderboard by Nick Watney (71), who had a 2-stroke lead with two holes to play following Mickelson's late struggles, but slipped to a double bogey at the 17th to result in the tie.
George McNeill (72) bogeyed his final hole to fall into third place at 7- under, while Lee Westwood (72), John Senden (67), David Lynn (71), Ryan Moore (68), Robert Karlsson (69) and Derek Ernst (72) share fourth at minus-6.
Former champion Rory McIlroy (73) is among a group of players tied for 10th at 5-under.
Mickelson was two ahead at the start of the day and was still two clear at the turn. Watney birdied the par-5 10th to move within one of Mickelson, who responded with 4-foot birdie putt on the same hole.
Watney drained a 19-footer for birdie on No. 11 to again move within one of Mickelson's lead. Mickelson missed the fairway off the tee at the 12th and that led to a bogey, which dropped him into a share of the lead with Watney at minus-10.
Mickelson's miss from four feet out was his first missed putt from inside 10 feet all week. He bounced back with a birdie on the 14th to regain the lead at 11-under.
The left-hander made a mess of the par-5 15th. His drive sailed into the right rough. Mickelson tried to cut a shot through the trees, but instead he hooked the ball out of bounds.
Mickelson hit his fourth short of the green, then chipped to five feet. From there, he 2-putted for bogey to slip one back of Watney. Mickelson coughed up another stroke at 16 after a poor second shot and then parred his last two.
"I don't know. After I made that putt on 14, I felt really good. I thought I could get one on 15. I got lucky on the tee shot that it didn't go out of bounds I missed it so bad, but the second shot should not have been a problem," Mickelson said. "It was a very easy lie to hit the shot I wanted to. I probably pulled the wrong club. I hit it the second time with the driver to get it to cut. I should have done that the first time.
"But I grinded it out. I felt like this could be a final round deal where we're getting so much rain tomorrow and Monday that we may not be able to play."
After five pars in a row, Watney stumbled down the stretch too. His tee ball at the par-3 17th found the rough. He chipped to the fringe, but 3-putted from nearly 70 feet out.
The double bogey dropped him into 3-way tie for the lead with Mickelson and McNeill. Watney parred the last to end at minus-8.
"I don't know what happened, to be honest. I was kind of fighting my swing all day, just trying to keep it in play. I hit a few shots off the heel with my driver and 3-wood off the tee, but obviously that was just terrible, a terrible result," said Watney of the 17th
"I haven't done that for a really long time. I can't remember really the last time I did that in a tournament, so it was a bit unsettling. But big picture, I'm tied for the lead, and I would have taken that on Thursday morning."
McNeill, who had four birdies and three bogeys through 15 holes, parred 16 and 17. At the last, McNeill tripped to a bogey to end one back. He will play alongside Mickelson and Watney in the final round though as players will go off in threesomes on Sunday.
"It went okay. I had a couple of loose swings at times, kind of the middle of the round was decent and then gave one back at the last, which doesn't make you happy," said McNeill. "But, overall, I felt like I played okay."
Mickelson bogeyed the third, but recovered that stroke with a birdie on the par-5 fifth. He rolled in a 9-foot birdie effort at the eighth to make the turn at 10-under.
Watney traded a birdie for a bogey from the first. He birdied the fifth and eighth, but tripped to a bogey on No. 9 to make the turn two behind Mickelson.
NOTES: With bad weather in the forecast for Sunday, tee times were moved up to 6:45 a.m. - 8:46 a.m. (ET) with players going off the first and 10th tees in threesomes ... McIlroy celebrated his 24th birthday on Saturday ... There was a secondary cut on Sunday with 11 players failing to move into the final round ... Among that group was 2012 champ Rickie Fowler, Mike Weir and Hunter Mahan.