Max Homa moved into position to defend his title at the Fortinet Championship, shooting a five-under 67 on Friday to share the 36-hole lead with Danny Willett at the PGA Tour's season opener.
Homa, a two-time winner last season and a captain's pick for next week's Presidents Cup, had an eagle, four birdies and a bogey - his first of the week - for a two-day total of 12-under 132 at Silverado Resort & Spa.
"The course fits my eyes," Homa said. "I hit a lot of wedges today and I've been hitting the wedges really well, so when I get a lot of wedges from fairways like these, I feel like I can attack the pins."
The four-time PGA Tour winner played collegiately at California.
"I've got a great support system here," said Homa, who won the 2013 NCAA individual title. "I've got friends and family up here and a bunch of, you know, people who appreciate I went to school up here."
Willett, winless in the US since his triumph at the Masters in 2016, shot a bogey-free 64. The English player kept his PGA Tour card for this season because of players defecting to the Saudi-funded LIV Golf series.
"Yeah, we kind of got handed a lifeline with the guys leaving, which was nice," Willett said. "We kind of had to reassess things and decided we'd press on and play a little bit more this fall over here and really try to get some points up early."
Willett has eight titles on the European tour, most recently last October at the Alfred Dunhill Links Championship in Scotland.
He had eight birdies in his second round and is bogey-free for the week.
"You know, the rough is hit and miss and with the greens being firm as they are. To go bogey-free is really good," said Willett, who has only six top-10 finishes on the PGA Tour since winning his lone major.
First-round leader Justin Lower and Byeong Hun An were two shots back. Lower had a 71. His best finish in 28 previous PGA Tour events dating to 2013 was a tie for eighth. An birdied the 18th and shot 68.
"It's always hard to follow up a very low round with another good round or even lower," Lower said. "But I will take one under today. Could it have been better? Yes, but it definitely could have been worse as well."
Taylor Moore (68), Matt Kuchar (68) and Sahith Theegala (69) were four shots off the lead.
Former world No.1 Jason Day, Harris English, Charley Hoffman and Webb Simpson were among the players who missed the cut.
Cameron Percy (68) at two under made the cut on the line along with fellow Australians Aaron Baddeley (69) and Harrison Endycott (70).
Endycott, who is making his PGA Tour debut, followed up Thursday's round of 18 straight pars with five birdies and three bogeys.