CHARLOTTE, North Carolina (AP) — J.B. Holmes shot a 6-under 66 on Saturday to take the outright lead at the Wells Fargo Championship, putting him a strong position to claim a richly deserved title after coming back from serious injuries.

Holmes overtook Martin Flores for the lead on the final hole at Quail Hollow, sinking a 20-foot birdie putt from the fringe of the green while Flores put his tee shot into an adjoining stream and then missed a putt of the same distance in attempting to save par.

Flores had a 69 to be a shot behind Holmes on 13-under 203. A stroke further back was Phil Mickelson, who roared into contention with a 63, including a run of six straight holes on the front nine which he played at 7-under.

Holmes had brain surgery in 2011 to remove a piece of his skull. Then, he broke his ankle in 2013, and time off allowed him to have surgery on his left elbow.

"I've worked really hard to get there and it would be a great accomplishment to come back and get a win in the bag," Holmes said.

Flores, whose best finish in four seasons on the PGA Tour was a tie for fourth in the John Deere Classic last year, never came close to a bogey until the 18th hole and believed in his title chances.

"I've been working really hard, feeling great about my game," he said. "I'm going to go out there and attack. If I win, I win. If I don't, I don't. I'm going to keep working until I do."

Mickelson was leading after he finished his superb round, but was subsequently overtaken by Holmes and Flores.

"Just to be in contention, and to have a chance at a golf course that I've become so close to over the years, I'm excited about tomorrow's round."

Kevin Kisner had a 68 and was three shots behind. Justin Rose bogeyed his last hole for a 71 and was four shots back, along with Jason Bohn, who made three birdies over his last four holes for a 67. Former PGA champion Martin Kaymer bogeyed his last two holes for a 70 and was five behind.

The last 54-hole leader to win at Quail Hollow was Anthony Kim in 2008.

That could bode well for Mickelson, off to his worst start to a season in 11 years.

Not since 2003 — the last year he went winless on the PGA Tour — has Mickelson gone this deep into a year without winning. Worse yet, he doesn't even have a top 10. He had to deal with a back injury in San Diego and an oblique muscle strain in Texas. He missed the cut at the Masters last month for the first time in 17 years.

"I had a good round today, and it feels good because it's been a rough year for me this year," Mickelson said. "I haven't been healthy early on and I haven't put it together. And to have a good round today, good round the first round, this is a good start."

Rory McIlroy set the pace early for a day of low scoring with a 65 that brought back memories of 2010, when he made the cut on the number and went 66-62 to win for the first time on the PGA Tour.

He was four shots behind that year going into Sunday, but this time is seven off the pace.