KJ Choi remained firmly in contention for his first PGA Tour win in almost five years as he retained a share of the lead at the Farmers Insurance Open.
Choi dug deep in tough conditions on the South Course at Torrey Pines and birdied the last hole to salvage a 72 which put him level with Scott Brown heading into the final round.
But a stormy finish is in prospect on Sunday as organisers brought forward the tee times due to the threat of adverse weather, and the players are likely to be forced to negotiate one of the toughest courses on Tour in winds of up to 40mph.
And with 23 players within four shots of the lead, Choi has his work cut out if he is to pick up his ninth PGA Tour title, and his first since edging out David Toms in a play-off at the Players Championship in 2011.
The Korean veteran hit back from a bogey at the fifth with an immediate birdie at the next, but a poor approach to the seventh left him in an awkward lie and he scrapped his way to a double-bogey six.
Choi dropped another shot at the 12th, but he staged a superb response over the last third of the round as he birdied the next two holes before a well-judged pitch to four feet at the last set up a closing birdie at the par-five.
Brown mixed five birdies with three bogeys in his two-under 70, although he failed to get up and down from a greenside bunker at the last as his eight-foot birdie putt for the outright lead missed the target.
The leading pair are one ahead of Jimmy Walker, who birdied the last two holes to post a creditable 68, while joint-overnight leader Gary Woodland was three over for his round until he birdied 15 and 18 to join Walker on eight under.
Jonas Blixt put together the round of the day, making birdies at four of the last six holes in a back-nine 31 which saw him return a 66 and get to seven under for the week - an outstanding effort considering he had opened the tournament with a 77.
Big-hitters Martin Laird (73) and Dustin Johnson (74) both slipped to six under, while Paul Dunne continued to impress on his PGA Tour debut as he compiled a solid 70.
The Irishman, who shared the 54-hole lead at last year's Open while still an amateur, offset four birdies with a pair of bogeys and closed four off the lead on five under.
Meanwhile, shot of the day went to Jason Gore as he recorded the first albatross of the season at the 18th - a towering fade with a three-wood from 250 yards which cleared the lake before landing softly and rolling straight into the cup.