Defending champion McIlroy is off to a strong start as Hisatsune leads

Defending champion Rory McIlroy made a strong start in 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.

Hisatsun, 23, was six at the turn and capped off an impressive performance with four more birdies back in the first PGA Tour marquee event of the season.

Northern Ireland’s McIlroy remains in contention six shots later after carding a four-under 68 in California.

But it was a case of what might have been for McIlroy, who opened with back-to-back birdies on the 10th and 11th holes and another on the 17th at Spyglass Hill, with his next front nine highlighted when he came out of a greenside bunker on the 14th for an eagle.

However, his lead was checked after the turn with a double bogey on all three holes – the third and fifth – when his putter cooled.

Although the world number two impressed in the second, fourth and ninth places, he still has a lot of ground to make up in the second round on Friday, although not as much as the man immediately above him in the rankings, Scottie Schaeffler.

The American, who has not finished outside the top 10 since last year’s Players Championship, struggled to a disappointing average of 72.

With the opening two rounds of the event split over two courses, Schaeffler’s friend and compatriot Sam Burns fared much better on the Pebble Beach Golf Links, finishing the day in second place on nine under alongside Keegan Bradley.

Chris Guttrup, a two-time winner already this season, has started with six straight birdies and is in good position at eight under with Tony Finau and Patrick Rodgers.

England’s Matt Fitzpatrick is six, while Tommy Fleetwood and Irishman Shane Lowry start strongly in the five-year-old with England’s Harry Hall close behind.

With a $20m (£14.7m) purse available, 18 of the world’s top 20 players will compete in the 80-player field, with Pebble Beach hosting rounds three and four on Saturday and Sunday.