Spaniard Jon Rahm made a flying start with three early birdies in his first round at the U.S. Open.
Rahm began his round at Pebble Beach at the 10th and picked up a shot there, before making further gains at the 11th and 12th to reach three under.
Ryder Cup player Rahm could have had four birdies in a row but missed from inside five feet at the 13th.
"Where I grew up in Northern Spain, it's somewhat similar to California. Very similar coastline and very similar golf courses. So I feel comfortable," said Rahm before the tournament.
It was a super start for a player bidding for a first major title, yet the 24-year-old at one stage had ground to make up on American Scott Piercy who had three birdies and an eagle in his opening six holes.
Piercy reached five under and has good memories of this tournament having finished in a tie for second three years ago at Oakmont.
However, a double-bogey six at the eighth brought Piercy back to three under and a share of the lead with Rahm.
Rahm has impressed before at major championships, finishing fourth at the Masters and US PGA Championship last year, and he also scored a ninth-place finish at Augusta this year.
Northern Ireland's Rory McIlroy, who won the Canadian Open last week, was one over through his first three holes but a birdie at 13 got him back to par.