Max Homa produced his best round of the week to erase a five-stroke deficit and win the Farmers Insurance Open with a score of 13 under.

Low scores were hard to come by on the difficult Torrey Pines South Course, with only three players posting final scores of 10 under or better, while Homa's 13 under was the worst winning score of the season so far.

Coming into Saturday's final round at seven under, Homa posted seven birdies and one bogey to shoot 66, tying the round of the day and finishing with a birdie on the last to win by two strokes.

It is the sixth PGA Tour win of Homa's career, and he now has back-to-back multi-win seasons after also collecting the opening event of the campaign at September's Fortinet Championship.

The only other player to shoot a six-under 66 in the final round was Keegan Bradley, flying up the leaderboard into outright second place at 11 under, while world number eight Collin Morikawa finished alone in third at 10 under. 

Sam Ryder was the outright leader after the second and third rounds, but he ended up in a tie for fourth at nine under due to a 75 in his final trip around the course that twice hosted the U.S. Open.

Coming into the event with four wins from his previous six starts, and starting Saturday at 10 under, Jon Rahm had to settle for seventh after a two-over 74, tying with former world number one Jason Day.

In-form Jon Rahm surged into contention at the Farmers Insurance Open on Moving Day at Torrey Pines but Sam Ryder remains two shots clear ahead of the final round.

The Spaniard, who started the day at four-under overall, carded an impressive six-under-par 66 on Friday to fly up the leaderboard to 10 under and be within two strokes of Ryder (12 under).

Ryder had held a three-stroke advantage at the halfway point and maintained his lead despite an even round that included one birdie, where he made a great save after hitting the cart path, and one bogey as the event switched to the South Course for the final two days.

World number three Rahm seemed to relish the conditions in an ominous sign ahead of the final round, with the second-best round of the day underlining his surge, that included a run of three straight birdies before an eagle on the ninth.

Rahm moved into outright second with the eagle, with an excellent approach on to the green followed by an 11-foot putt. The 28-year-old claimed his first PGA Tour victory in 2017 at Torrey Pines.

Tony Finau enjoyed the best round of the day, carding an eight-under-par 64 to move into outright third at eight-under overall.

Finau, who was the only player to go bogey-free, had six birdies plus an eagle on the par-four first hole when he holed out from 138 yards on his approach.

A group of four players are tied for fourth at seven-under overall, in Sungjae Im, Collin Morikawa, Max Homa and Sahith Theegala.

Sam Ryder is in a strong position to make a run at his first PGA Tour victory as he heads into the weekend at the Farmers Insurance Open with a three-stroke buffer atop the leaderboard.

Ryder, 33, has not collected a professional win since his Web.com Tour triumph back in 2017, but after banking a second-place finish in 2021 and a third-place result in 2022, he now has his best chance at a PGA Tour title.

The American owned a share of the lead after an eight-under 64 in his opening round on the Torrey Pines North Course, and he followed it with a four-under 68 on the South Course during Friday's second round. The final two rounds will be played on the South Course, which has hosted the U.S. Open twice.

Ryder's co-leaders after 18 holes both had far more trouble on the South Course, with Brent Grant posting a two-over 74 to drop to six under, while England's Aaron Rai shot himself out of contention with a six-over 78.

Alone in second place is Ryder's playing partner from the first two days, Brendan Steele, who went two under on the more difficult South Course to reach the weekend at nine under.

Incredibly, Steele is the only player within five strokes of the leader, with Argentina's Tano Goya sitting in solo third place at seven under.

Despite Grant's massive drop-off, he still owns a share of fourth place at six under, where he is part of a six-man group including Max Homa and Sahith Theegala.

Former world number one Jason Day and current top-10 talent Collin Morikawa round out the top-10 at five under, while Jon Rahm, who has won four of his past six starts, is one further back at four under.

Luke List has had a long wait for his first PGA Tour win and that was extended after a two-hour wait before triumphing in a playoff over Will Zalatoris at the Farmers Insurance Open on Saturday.

The 37-year-old American, enjoyed an excellent final round six-under-66, highlighted by four consecutive birdies from the third to the sixth holes, to storm up the leaderboard at Torrey Pines.

But List, in his 206th career start, waited almost two hours after entering the clubhouse as the overnight leaders completed their rounds before facing Zalatoris, who also finished 15-under overall, in an 18th hole playoff.

In fading light, the pair both landed their tee shots within inches of each other in a bunker, with List's third shot placed close to the hole, enabling him to tap in to card a birdie.

Zalatoris pushed his longer birdie putt, which was near-identical to his 18th hole putt for victory that he missed, wide left again to settle the playoff in List's favour.

California-born 25-year-old Zalatoris may have clinched victory on the 18th as List patiently waited and practiced elsewhere, but was agonizingly short and slightly wide after a late fade on his putt.

He carded a final round one-under-71, grouped alongside Jason Day and Aaron Rai, with world number one Jon Rahm also making a late charge.

Day shot into a share of the lead after landing an eagle on the 14th hole but had to settle for joint third alongside Rahm and Cameron Tringale at 14-under-par overall.

The Australian, who had not won a PGA Tour title in 1,364 days, finished with back-to-back bogeys to slip from contention.

Rahm rolled in a clutch 26-foot putt to birdie the 17th to be one shot off the pace but only managed par on the last hole.

Joaquin Niemann, Justin Rose, Pat Perez, Sungjae Im and Rai were next, finishing 13-under overall.

Will Zalatoris goes into the final round of the Farmers Insurance Open with a first PGA Tour win in his sights after a superb performance on day three.

Zalatoris claimed a share of the 54-hole lead with Jason Day thanks to a seven-under-par 65 at Torrey Pines.

That took him to 14 under, level with 2015 US PGA Championship winner Day, who carded a 67.

Zalatoris had started the day six strokes adrift of midway leaders Jon Rahm, Justin Thomas and Adam Schenk.

But an eagle at the par-four second gave him early momentum and five further gains followed in a blemish-free round for last season's Rookie of the Year.

That eagle featured a 338-yard tee shot as a day Zalatoris described as perhaps the best with the driver "maybe ever" put him in position to push for a maiden tour win.

Asked how much distance he has gained following a switch to a 46-inch driver, Zalatoris replied: "Twelve yards, I've clocked it up to 127 [mph clubhead speed] and have 186 ball speed so, around here, that's huge.

"Obviously you've seen what Bryson [DeChambeau] has done, you won't be seeing me at 220 [ball speed] anytime soon but definitely the added distance has really paid dividends."

Along with Day, Zalatoris still has Rahm in his rear-view mirror, a level-par 72 keeping him at 13 under, tied for third with Aaron Rai.

Rahm carded a double bogey at the 10th and lost another shot at the 12th, but he will hope his experience of winning the U.S. Open at Torrey Pines last year can help him recover on Saturday.

Thomas, meanwhile, carded a one-over 73 and has Cameron Tringale and Sungjae Im for company on 12 under.

Adam Schenk carded a 10-under-par to surge into a share of the lead alongside top-ranked Jon Rahm and Justin Thomas at the halfway mark of the Farmers Insurance Open on Thursday.

Schenk, who is ranked 54th and has never won a PGA Tour title, carded a career-best PGA Tour round of 62, which included making 10 birdies and hitting four of 14 fairways.

The American, who turned 30 on Wednesday, made eight consecutive birdies was within one shot of equaling the course record, with his 15-feet putt on the 18th hole lipping out.

Reigning US Open winner Rahm, who opened the tournament with a six-under-par 66, backed up with a seven-under-round on the second day on the North Course at Torrey Pines.

World number six Thomas is locked with Schenk and Rahm at 13-under overall after his nine-under round.

The trio lead from Cameron Tringale at 12-under, with Peter Malnati next with 11-under.

Opening day leader Billy Horschel slipped down the leaderboard after a one-over round to be eight-under overall.

Will Zalatoris, who started and finished the second day with eagles, is among a group of six at seven-under including Dustin Johnson.

Phil Mickelson, Bryson DeChambeau, Jordan Spieth, Rickie Fowler, Tony Finau and Brooks Koepka were among the notable players to miss the cut.

Spieth's four-over card ended his run holding the longest active made-cut streak (20) on the PGA Tour.

Billy Horschel leads the way after the opening day of the Farmers Insurance Open in San Diego with world number one Jon Rahm the best of the big names in the field.

Horschel leads by one stroke from Michael Thompson after the 35-year-old American carded a bogey-free nine-under-par 63 on the North Course at Torrey Pines.

World number 23 Thompson also went bogey free on Thursday, birdieing four of his first five holes to jump out of the blocks, before birdies on the 17th and 18th holes rounded out a strong day.

Stephan Jaeger and Kevin Tway are seven-under-par, with Rahm on six-under-par alongside three others players; Rickie Fowler, Doug Ghim and Francesco Molinari.

Rahm's round on the South Course included two bogeys and six birdies but he jumped up the leaderboard with an eagle on the 18th.

Sam Burns, Daniel Berger and Tony Finau are among a group of players tied at five-under while Justin Thomas started with a four-under-par 64 but had five birdies on his front nine before two bogeys in his final five holes.

Tokyo Olympics gold medallist Xander Schauffele and 2020 Masters champion Dustin Johnson are also four under.

A bleach-blonde Brooks Koepka had two bogeys and four birdies to be two under, alongside three-time major winner Jordan Spieth and 2020 US Open champion Bryson DeChambeau.