Former world number one Jordan Spieth holds a one-shot lead at the AT&T Pebble Beach National Pro-AM, but he is not alone atop the leaderboard as fog cut short play in the second round.

Spieth was fortunate to complete his round as most of the field failed to do so due to the weather, with the two-time major champion carding a seven-under-par 65 on Friday.

After returning early to complete the final two holes of his first round for a 68, Spieth holed eight birdies and dropped just one shot at the Spyglass course to be 10 under through 36 holes.

Fellow American Derek Fathauer is also 10 under, though he was through 17 holes when play was suspended.

Fathauer was flawless on day two, with eight birdies to his name as he prepares to resume his round at 07:30 (local time).

World number one Jason Day is within striking distance at Pebble Beach.

Day only completed 12 holes but the Australian was seven-under-par and only a stroke adrift of Spieth and Fathauer.

Patrick Reed (through 17) and Noh Seung-yul (through 13) are seven under overall, while Pat Perez (through 17) and Joel Dahmen (through 11) are a shot further back.

Martin Flores (68) was the only player among a group of five tied for eighth position to finish his round.

Meanwhile, Jon Rahm rocketed up the leaderboard following his second-round 67.

Rahm reeled off six successive birdies to improve 44 positions, up to 13th, alongside Dustin Johnson (69).