Defending champion Rory McIlroy made a solid start to the first round of the AT&T Pebble Beach Pro-Am as Japan’s Ryo Hisatsune set the early pace with a 10-under 62.
Hisatsune, 23, was six under at the turn and concluded a stunning performance with four more birdies on the back nine on the PGA Tour’s first signature event of the season.
Northern Ireland’s McIlroy is still in contention six shots back after carding a four-under 68 in California.
But it was a case of what might have been for McIlroy, who opened with consecutive birdies on the 10th and 11th holes and another on the 17th at Spyglass Hill, with the highlight of his front nine coming when he chipped out of a greenside bunker on the 14th for an eagle.
However, his progress was checked after the turn with double bogeys at the two par-three holes – the third and the fifth – when his putter ran cold.
While the world number two picked up shots on the second, fourth and ninth, he has ground to make up in Friday’s second round, although not as much as the man directly above him in the rankings, Scottie Scheffler.
The American, who has not finished outside a top 10 place since last year’s Player’s Championship, struggled to a disappointing even par 72.
With the opening two rounds of the event split across two courses, Scheffler’s friend and compatriot Sam Burns fared much better at Pebble Beach golf links, to end the day in second on nine under alongside Keegan Bradley.
Chris Gotterup, a two-time winner already this season, began with six successive birdies and is well placed at eight under along with Tony Finau and Patrick Rodgers.
England’s Matt Fitzpatrick is at six under and Tommy Fleetwood and Ireland’s Shane Lowry made solid starts to sit at five under with Englishman Harry Hall one further back.
With a $20m (£14.7m) purse available, 18 of the top 20 players in the world are competing in the 80-man field, with Pebble Beach hosting Saturday and Sunday’s third and fourth rounds.