Denny McCarthy, chasing his first US PGA Tour triumph, closed with a seven-foot eagle putt to grab a one-stroke lead after Thursday's rainy first round of the Genesis Invitational.
The 31-year-old American fired a four-under par 68 at shower-softened Torrey Pines near San Diego, where the event was moved from Riviera due to Los Angeles wildfires damage.
Players battled cold, windy and rainy conditions, with McCarthy's first Torrey Pines visit in four years off to a brutal but successful start.
"I'm a grindy competitor so I knew it was going to be a challenge and I came out with the attitude that I was just going to have fun and try to embrace it as much as I could," McCarthy said.
"Was a huge help to play the pro-am yesterday in even nastier conditions, so it prepared me really well for the shots I knew I was going to face."
Ireland's Seamus Power and American Patrick Rodgers shared second on 69 with Americans Wyndham Clark, Davis Thompson and Scottie Scheffler sharing fourth on 70.
MISSING PUTTS
Top-ranked Scheffler lipped out from just inside four feet on a birdie putt at the par-5 18th to stay two adrift.
"Very difficult to score. It got pretty windy out there and that makes it difficult to putt," Scheffler said.
"Missing putts is something that's going to happen. You can hit putts that not go in but I did a pretty good job of staying patient," added Scheffler, whose nine victories last year included Paris Olympic gold, his second Masters green jacket and the PGA Tour Championship.
World number 50 McCarthy's best PGA career finishes have been playoff losses in last April's Texas Open and the 2023 Memorial tournament.
McCarthy sank a 42-foot birdie putt from the fringe on the first hole, shook off bogeys at the par-3 third and par-4 fifth with birdies at the par-5 sixth and par-3 11th.
He made a birdie putt at 15 from just inside 20 feet, missed the green to bogey the par-3 16th, sank a 25-foot birdie putt at 17 and dropped his second shot at 18 to seven feet, setting up his eagle.
"It was very difficult, especially with the rain and the rough length. The rough's gnarly and the rain makes it even more difficult," said McCarthy.
"Even though the greens are soft, it was still really hard to get close to certain flags, especially with the wind direction."
Power birdied two of the last four holes, sinking a birdie putt from just outside 10 feet at 15 and landing his approach inside three feet at 17 to set up a tap-in birdie.
"Toughest part was just getting it on the fairways," Power said. "You're wearing extra layers. It almost feels harder in these sort of conditions and as soon as you miss a fairway you're in big trouble."
Rodgers birdied the last two holes, sinking an 11-foot birdie putt at 17 and finding the par-5 18th green in two to set up a tap-in birdie.
"You're just trying to get back under the umbrella or get the heated mitts back on," Rodgers said.
'IT WAS PRETTY CRAZY'
Scheffler birdied the second from just inside 14 feet and the fourth on a five-foot putt.
After a three-putt bogey at the fifth, he answered with a tap-in birdie at the par-5 sixth and a 10-foot birdie putt at the seventh.
Scheffler found deep left rough on a bunker's edge at 14 and his approach sank in greenside rough on the way to a bogey before his birdie miss at 18.
"Everything was wet out there. It was pretty crazy," Scheffler said. "You just had to manage your way around the golf course and know par is a really good score."
World No 3 Rory McIlroy, a winner two weeks ago at Pebble Beach, was in a pack on 72.