Shawn Stefani overcame a quadruple bogey on the 11th to card a 4-under 66 and grab a 1-stroke lead after three rounds of the FedEx St. Jude Classic.
Stefani, a two-time winner on the Web.com Tour last year, finished 54 holes at 12-under-par 198. He will go for his first PGA Tour win on Sunday.
Second-round leader Harris English managed a 1-under 69 in round three and dipped into second place at minus-11 at TPC Southwind.
Patrick Reed fired a 6-under 64, the low round of the day, to move into a share of third place at 8-under-par 202. He was joined there by Nicholas Thompson (66) and Scott Stallings (67).
Phil Mickelson posted a 5-under 65 and he joined Eric Meierdierks (66) in sixth at minus-7. Meierdierks had a hole-in-one on the par-3 eighth. Padraig Harrington and Ryan Palmer both shot 65 on Saturday. They stand alongside Roberto Castro (67) in eighth at 6-under 204.
Defending champion Dustin Johnson (68) is among seven players tied for 11th at minus-5.
English was two clear of Stefani to start the day and he birdied the first from 12 feet out to push his advantage to three. Stefani responded with a 5- foot birdie putt at the second.
At the par-5 third, both players converted birdie chances from inside four feet. English remained two clear, but that quickly changed.
English hit a poor drive on the fifth and that led to a bogey. After a pair of pars, he missed the green at the par-3 eighth and walked off with another bogey. The duo was suddenly tied for the lead, but Stefani was about to make his move.
Stefani, who has missed eight cuts in 14 starts this year, converted a 6- footer for birdie on the ninth and moved two clear of English with a 12-foot birdie putt at No. 10. English was in the midst of nine straight pars from the ninth, but Stefani kept things interesting.
The 31-year-old Stefani dumped his tee shot in the water at the par-3 11th. His third from the drop zone flew the green and buried in a sand trap. He left his fourth in the sand, then blasted his fifth shot to four feet. Stefani 2- putted for a quadruple bogey, which dropped him two back of English.
"It's tough to watch that, I don't care who you are. I'm pulling for him, I'm pulling for anybody that I'm playing with. I'm just trying to obviously beat him. It was tough to watch that," English joked of Stefani's quadruple bogey. "But he brought it back beautifully and played some solid golf."
Stefani came back with an 11-foot birdie effort at the 14th to get one stroke back. He grabbed a piece of the lead with a 3-foot birdie putt at the par-5 16th. Stefani made it two in a row as he rolled in a 17-footer for birdie at the 17th.
At the last, English ended his run of pars with a 14-foot birdie putt to get in at minus-11. Stefani answered with an 8-footer for birdie to end one clear.
"It's funny. I actually hit a good shot, I just pulled the wrong club with the wrong wind. It just happens," Stefani said of his quadruple bogey. "It was a good day. It actually helped to have Harris along because he's a great young player and we have a lot of similarities in our lives. It was great, I had a great time with him and I'm looking forward to it tomorrow."
English tied for fifth at Colonial last year and has just three top-10s this season.
"This golf course is tough. You've got to hit fairways and greens. Even though I didn't make many birdies out there, I didn't make many putts," English stated. "But I'm happy with steady golf."
NOTES: English, like Stefani, is looking for his first PGA Tour victory ... Stefani's best tour finish is a tie for seventh earlier this year in Tampa Bay ... Six out of the last seven winners have come from behind in the final round to grab the title ... Twenty-three of the 37 players in this week's field that are playing next week in the U.S. Open made the cut.