Brian Gay and Scott Langley are tied atop the AT&T Pebble Beach Pro-Am leaderboard after round one, but Phil Mickelson stole the show on the fairway.

Gay and fellow American Langley carded seven-under-par 64s for a one-stroke lead in Pebble Beach on Thursday.

Mickelson is in a six-way tie for third place following his memorable 65, which saw the American star hit every single fairway for the first time since 1998.

Five-time major champion Mickelson started his round with a birdie on the par-four first hole. He made a bogey and another birdie before the turn.

On his back nine, the 43-time PGA Tour champion tallied five birdies at Monterey Peninsula Country Club.

The opening round was the first time since in more than 20 years that Mickelson – who was also 17 of 18 on greens in regulation and had 32 putts – hit all 13 fairways

"To the best of my knowledge it's taken me 27 years and a few months to hit all fairways in a single round in a competition," said Mickelson, who initially believed it was the first time he had accomplished the feat. "I may have done it before but I don't ever recall doing it."

Former world number one Jason Day – tied for second at last year's tournament – joins Mickelson in third, while defending champion Ted Potter Jr sits at the very bottom of the leaderboard following his forgettable 10-over-par 82.

Dustin Johnson and Jordan Spieth round out the top 10 in a sizeable tie for ninth place following their 66s, which left the pair two strokes off the pace.

Johnson had six birdies and a bogey to be within touching distance, while Spieth – seeking his first title since 2017 – managed seven birdies and two bogeys following a flawless back nine.

"I'm really happy about the back nine. The putts went in instead of missing," Spieth said.