LOS ANGELES — Riviera felt like a roller coaster to Phil Mickelson to the very end.

Never mind the four scores he put together at the Northern Trust Open to successfully defend his title on Sunday. He opened with a personal-best 63 and was nine shots worse the next day. Butch Harmon arrived Saturday morning to help stabilize his swing, and Lefty went even lower with a 62 to take command.

Then came another 1-over 72, and it was just enough to avoid the biggest collapse of his career.

Mickelson rolled in a 6-foot par putt on the 18th hole for a one-shot victory over Steve Stricker, and while it wasn't the most memorable of his 35 career victories on the PGA Tour, it was no less satisfying.

"It gives me confidence and something to build on for the rest of the year," Mickelson said. "Even when I didn't have my best stuff, I was able to fight through it."

Stricker closed with a 67, making bogey on the 18th hole that he knew would cost him.

Another stroke back was the real heartbreak of Riviera — Fred Couples, 49 and in his last full season on the PGA Tour, rejuvenated on a course where he has won twice and considers his favorite this side of Augusta National. Couples missed two birdies inside 8 feet on the front nine, and trailing by only one shot on the 18th, fanned a shot into the eucalyptus trees and made bogey for a 69.

He tied for third with Andres Romero (70) and K.J. Choi (69).

Mickelson joined Ben Hogan, Corey Pavin and Mike Weir as the only repeat winners at Riviera, and he felt a sense of relief and satisfaction as he hoisted the trophy beneath the fabled clubhouse off Sunset Boulevard.

He was in a position he had never been in during his 17 years on tour, then in a spot that was all too familiar.

Starting the final round with a four-shot lead, Mickelson watched his tee shots fly all over Riviera.