LOS ANGELES (AFP) - Jason Dufner, seeking his first USPGA Tour title since the 2013 PGA Championship, fired an eight-under-par 64 to seize a two-stroke lead after Saturday's third round of the CareerBuilder Challenge.

The 38-year-old American began off the 10th tee at La Quinta, one of three par-72 courses used over the first three rounds in the southern California desert, and birdied seven of his last nine holes to stand on 23-under 193 after 54 holes.

"I have been playing good," Dufner said. "I told my partners (at the turn) I was going to do something good and it just happened. That's where my mindset is right now."

American Jamie Lovemark, playing on the TPC Stadium Course at PGA West, fired a third consecutive 65 on his 28th birthday to grab second on 195, one stroke in front of Canada's Adam Hadwin, who shot 64 on the Nicklaus Tournament Course.

After opening with a bogey, Dufner birdied three of the next four holes before a bogey at the par-3 15th. Then came his fantastic finish, a seven-under 29 on his inward nine.

"I never feel like I have to do anything because I'm playing good. You just keep playing. It just helps when you shoot 30s and 29s," he said. "I feel good about where my game is. Conditions are pretty good for scoring. I'm confident with whatever club I've got in my hand."

Dufner has two other PGA victories as well as his major title, having won at New Orleans and the Byron Nelson Championship in 2012.

Sweden's David Lingmerth was fourth on 198 after a 62 on the Nicklaus layout, one stroke ahead of Americans Kevin Na, Andrew Loupe, Ryan Palmer, John Huh and five-time major winner Phil Mickelson.

Mickelson has three rounds in the 60s for the first time since his runner-up effort at the 2014 PGA Championship after working on swing changes.

"It has been a good three days," Mickelson said. "It feels easy. I haven't been fighting anything. What I'm trying to get back is the touch, the nuances, the subtleties. As I work to get it back on, it feels easy again."