(CNN) -- Defending champion Phil Mickelson returned to form with a vengeance as he took the first round lead at the Northern Trust Open in Los Angeles with a sparkling eight-under 63.
Mickelson showed improved form on the first day of his Northern Trust Open defense.
Mickelson has performed poorly in his opening three tournaments of the PGA Tour season, but again showed his liking for the Riveira Country Club to take a one-shot lead when play was suspended with four golfers still on the course.
Fellow-American Scott McCarron is his nearest challenger, with a group of seven golfers which include last week's winner Dustin Johnson and Jim Furyk a further two shots back on five-under.
Also tied for third place are European Ryder Cup star Luke Donald, Korea's KJ Choi, John Merrick, Dean Wilson and Andres Romero.
Mickelson was pleased to be back to his best, telling Press Association that his low score was built on an improved short game.
"It was a good start and I feel like I'm back on the right track," he said. "At least my misses were much better. I felt much better with the putter and my short game was as good as it's been. I hit a lot of good shots around the greens to save strokes."
The left-hander put his slow start to the season, finishing no higher than 42nd, due to some equipment changes. "I was trying a little bit different shafts with some of my irons and wasn't quite matching up the way I would like, so I just went back to my set from last year and tried to eliminate any variables," he added.
Pebble Beach National Pro-Am winner Johnson said his recent successes are down to hard work.
"You know, I've been working pretty hard on the game and it's feeling good right now. Everything is going well. Everything feels really good."