Phil Mickelson is tied with Keegan Bradley at the top of the Northern Trust Open leaderboard.
The 41-year-old posted a one-under-par 70 for his third round at the Riviera Country Club, leaving him on seven-under-par for the championship.
USPGA Champion Bradley shot a joint-best 66, along with Aaron Baddeley and Bryce Molder.
"Tomorrow is a big day for me," said the 41-year-old Californian. "I've led all the way and I would like to do it to the finish.
"I love this golf course, I'm ready and I'm focused on tomorrow's round. I've got a couple weeks off after it.
"I'm going to put everything I have into it to see if I can bring out some of my best golf."
Mickelson triumphed at Riviera CC in 2008 and 2009, and will be hunting his 41st PGA Tour title.