Ernie Els and Paul Casey go into the final round of the Frys.com Open two shots behind leader Briny Baird.
American Baird stormed round the CordeValle Course in 64 to reach 13 under for the week in California.
Halfway leader Casey was bogey free for his third round, but failed to take full advantage of excellent scoring conditions with three birdies in his 68.
South African Els had a brilliant eagle at the par five ninth, nailing his approach to eight feet.
That was mixed with four birdies and two bogeys as the three-time Major winner moved closer to what would remarkably be his first top-ten finish on the US PGA Tour in 2011.
Tiger Woods shot a second successive 68 to move to four under.
Baird has not won a US PGA Tour event in more than 12 years on tour, having made more money than any player without a victory with more than US $11,900,000 in career earnings.
Also notable were the performances of Jim Renner and Will Mackenzie who set a course record with their rounds of 62, propelling both men 58 places up the leaderboard into a four-way tie for ninth.
As Baird stands on the brink of a first tournament win, it was suggested he could emulate Kevin Na who went 210 starts without victory before finally triumphing in Las Vegas last week.
Baird, though, told pgatour.com: "I don't look at it like if he can do it, I can do it.
"There's been guys that have played out here for a while that suddenly win a golf tournament. It's going to be - my world is not going to come to an end if I play well tomorrow and win the golf tournament.
"I think it's more of a bucket list type thing.
"I used to say it's not going to bother me.
"But I think looking back on it, it probably would bother me if I never did win on the PGA Tour.
"Feeling like you can win on the PGA Tour and winning on the PGA Tour are as different as black and white."
Els has 18 Tour wins and said: "This is what I've been working toward, especially after the PGA.
"I changed a lot of things and I feel that the work I've put in is starting to come through."
Casey has just one career win on the US PGA Tour, in 2009, though he has won twice elsewhere in the world this season, most recently in South Korea last week.
"I take a lot of confidence out of last week," said Casey, who has been plagued by a foot injury all year.
"Not just the win but I felt that the game is coming back to where I want it to be.”
