Phil Mickelson followed up his blistering opening-round 60 with a 4-under-par 68 on Friday at PGA West's Nicklaus Stadium Course to take a two-shot lead into the weekend at the Desert Classic in La Quinta, Calif.

He holds a two-shot lead over Australian Curtis Luck, who sits in second place after shooting a 6-under 66 also on the Nicklaus course.

As on Thursday, when he made 10 birdies and an eagle, Mickelson finished with a birdie on his 18th hole, but that was where the similarities ended. He started on the back nine and turned with an even-par 36 after a double bogey on No. 9, but birdies four of his last five holes to salvage his day.

"I actually felt better striking (the ball). I didn't putt very well today, certainly relative to yesterday where I was making everything," said Mickelson, a two-time winner of the Desert Classic (2002, 2014). "But I finished strong. I birdied four of the last five. You know, if you shoot 6 or 7 under par at the Nicklaus course, you feel like OK, that's a good solid round. I shot 4 (under), I was a few behind, so I'll just have to come out tomorrow on the Stadium (Course) and shoot 6 or 7 (under) to make up for it."

Mickelson was even through No. 13 after failing to make birdie on the par-5 fourth. However, a birdie from 8 feet on No. 5 turned the momentum.

"I just needed one little spark," Mickelson said. "Once that one went in, I started seeing the ball go in a little bit easier rather than the ball lipping out and I made some putts thereafter. ... You just have to keep firing on all cylinders and going after birdies because this is a course where there's going to be a lot of birdies."

The Desert Classic is a pro-am format, with players rotating among two courses at PGA West, the Nicklaus Tournament Course and the Stadium Course, and nearby La Quinta Country Club over the first three days. All three courses are par 72. Sunday's final round will be played at the Stadium Course.

Last season, the Nicklaus Tournament Course yielded the second-lowest average score (69.445) of any par 72 on the PGA Tour last season. La Quinta was No. 1 (68.831), while the Stadium Course yielded an average of 71.181.

Luck, 22, closed with a birdie on the par-4 ninth, taking out some of the sting from a bogey on the par-3 eighth.

"Just like yesterday, very solid, lot of greens, a lot of fairways," said Luck, the 2016 U.S. Amateur champion. "Just missed a couple of short ones today, unfortunately. But putting's been great."

Adam Hadwin (66, La Quinta) and Steve Marino (65, La Quinta) are tied for third at 13 under. Defending champion Jon Rahm of Spain (Nicklaus) fired his second straight 66 to move to 12 under with Wyndham Clark (67, Nicklaus) and Joey Garber (64, La Quinta).

As for the possibility of capturing the title, Mickelson says experience is on his side but he's taking nothing for granted. He has won 17 of the 32 times on the PGA Tour when he's held the 36-hole lead.

"This has been a fun if not surprising start for me, and it's been fun to get in the mix," he said. "Usually when you play that well the first two rounds, you're hitting the ball where you want, making some putts, so I just have to keep that going the next couple days."