Frost will be shooting for his third career Champions Tour victory when he enters Sunday's final round at 13-under-par 139 at Newport Beach Country Club.
That's one shot better than 2010 winner Fred Couples, who kept up the pressure on Frost by matching the leader's second-round score. Couples ended the day at minus-12.
Grabbing sole possession of third place at 8-under 134 was Jim Gallagher Jr., who turned in a round of 3-under 68.
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