LOS ANGELES — Phil Mickelson seems determined to add Los Angeles to his collection of West Coast trophies.

A year after losing at Riviera in a playoff, Mickelson played golf as spectacular as the weather today in the Northern Trust Open, finishing with a 20-foot birdie putt on the final hole for a 7-under 64 and a four-shot lead.

Even after starting with a 68, Mickelson felt he was close to putting his game together. It started with a 3-iron to 12 feet on the par-5 first for a simple birdie, and built momentum with a 60-foot birdie on the fifth and never slowed.

When he finished his best score ever at Riviera, he was at 10-under 132 and in firm command going into the weekend.

"This is a tournament that has eluded me," Mickelson said of the only city in the West Coast Swing where he hasn't won. "The West Coast means a lot to me."

Robert Allenby, who won at Riviera in 2001 in the cold and rain, did OK in warm sunshine with a 66 that put him at 136 with Jeff Quinney, who made bogey on the final hole for a 67.

Mickelson and the top dozen players atop the leaderboard got one big break with the draw by playing early Thursday and in the afternoon Friday, essentially avoiding the strongest of the wind that gusted along the eucalyptus trees lining the fairways.

For those who faced a cold wind Thursday afternoon and more swirling breezes Friday morning, the best anyone could muster was David Toms (68) and Kevin Sutherland (69), each at 3-under 139.