Jon Rahm charged into the Farmers Insurance Open lead after firing a seven-under 65 on Saturday, while Tiger Woods was left five shots adrift.
Rahm produced a bogey-free third round at Torrey Pines in California, where all players were on the South Course, making an eagle and five birdies.
The Spanish 2017 champion holed out from 111 yards at the par-four second after a birdie at the first before picking up shots at the sixth and ninth.
Rahm made further birdies at 13 and 16 to get to 12 under, holding a one-stroke lead over Ryan Palmer (71).
Rory McIlroy produced his equal best round of the tournament with a five-under 67 to get to nine under and a tie for third.
The Northern Irishman sits alongside Sung Kang (67), Harry Higgs (69) and Cameron Champ (68) heading into the final round.
Woods, meanwhile, made a brilliant start by holing four birdies on the front nine to get to within two of the leaders in San Diego, where there was a two-hour delay to the start of play due to heavy fog.
A bogey at 11 slowed him down and although he made a great par save at the last, the seven-time champion appears too far back.
Tyler McCumber (68), Tony Finau (68), Marc Leishman (68), Patrick Reed (70), Sebastian Cappelen (71), Brandt Snedeker (72) and J.B. Holmes (71) are a shot ahead of Woods in equal seventh.
Jordan Spieth is back in a tie for 42nd after a one-over 73, although he did manage to hole out for birdie from 87 feet from the rough for birdie at the 15th.