PEBBLE BEACH (REUTERS) - Phil Mickelson's seven birdies more than made up for three bogeys as the veteran American finished atop the leaderboard with four other players at the Pebble Beach Pro-Am in Northern California on Friday (Feb 8).

Weather conditions deteriorated throughout the day as rain and wind set in and play was suspended before a handful of players could finish their rounds, which had begun an hour earlier than scheduled to avoid the worst of the storm.

Mickelson (four-under 68), Lucas Glover (66), Scott Langley (69) and Paul Casey (64) all sat at 10-under par alongside Jordan Spieth, who was on the 16th when play was called for the day.

After an opening round where he did not miss a fairway for the first time in two decades, Mickelson struggled with his accuracy off the tee on Friday and had consecutive bogeys on holes six, seven and eight.

"I didn't drive it like I did yesterday," the 48-year-old left-hander said. "Here you've got to be in the fairway and I was fractionally off on a couple of holes. Both par fives in the front and that ended up costing me probably three shots if I hit those fairways."

But his solid putting bailed him out and he credited his familiarity with the course's tricky poa annua greens for his success at the tournament, where he is a four-time champion.

"I grew up in California and I'm used to the poa greens," he said. "I think that's a big adjustment for a lot of guys, seeing how the ball rolls on that particular grass and adjusting to the soft conditions.

"But growing up here, you get used to it and figure it out."

Englishman Casey had the best round of the leaders on Friday, firing five birdies and an eagle en route to a bogey-free round at Monterey Peninsula, the easiest of the three courses used during the tournament.

Wet and chilly conditions are expected to return on Saturday, when the first players will go out at 7.10am local time.