Billy Horschel fired a nine-under-par 63 to snatch the early lead the PGA Tour's Farmers Insurance Open at Torrey Pines on Wednesday.
Horschel reeled off nine birdies and nine pars in a flawless opening round at the picturesque southern California layout's North Course to lead by one shot from Michael Thompson on eight under.
The 35-year-old's brilliant round saw him grab the lead on the 520-yard par-five 17th hole, when he reached the green in two before two-putting for birdie.
Horschel revealed after his round he had been close to withdrawing after struggling to overcome a shoulder problem.
"I didn't know if I was even going to tee it up today when I woke up," the 2014 FedEx Cup champion said. "Even when I was hitting balls I still wasn't sure whether I was going to tee it up."
A low-scoring opening round saw Germany's Stephan Jaeger and Kevin Tway finish the day on seven under after posting 65s, while there was a welcome return to form for Rickie Fowler, whose form and rankings position nosedived during a 2021 season that included nine missed cuts.
World number 101 Fowler, who also missed the cut at last week's American Express at La Quinta, was tied in fifth place with Doug Ghim, Italy's Francesco Molinari, and world number one Jon Rahm on six under.
Fowler's bogey-free 66 on the North Course included six birdies.
"Definitely pleased," Fowler said afterwards. "Did a good job of kind of focusing on the things that we're working on, being deliberate swing-wise and staying patient in there."
Spanish star Rahm meanwhile, making a happy return to Torrey Pines, the scene of his maiden major victory at the US Open last year, had a more erratic opening round on the South Course.
After three birdies on the front nine to reach the turn at three under, Rahm posted three birdies and two bogeys in five holes down the stretch to struggle to four under.
But a superb eagle three on the par-five 18th - reaching the green in two before curling in an awkward 12-foot put - left him just three off the lead.
Rahm was pleased at being able to salvage a low score despite the occasional wayward shot.
"I put myself in really good positions, and the few times I was off, for the most part I was able to give myself a chance to save the hole," Rahm said.
"Nothing was really bad, I feel like everything was feeling good, everything was coming out and feeling the way it should and it showed in the score."
A group of 22 players were a further shot behind Rahm, Fowler, Ghim and Molinari on five under.
Former world number one Dustin Johnson was in a group of seven players on four under after opening with a 68.
Comments are moderated and generally will be posted if they are on-topic and not abusive.
For more information, please see our Comments FAQ