The win helped Mickelson climb two places to No. 3 in the latest world rankings.
World No. 1 Tiger Woods returns to action this week to defend his title at the WGC-Accenture Match Play Championship.
Sergio Garcia held steady in the second spot. Mickelson's move to No. 3 bumped Padraig Harrington and Vijay Singh down to four and five respectively.
Henrik Stenson held steady in sixth place and was again trailed by Robert Karlsson and Geoff Ogilvy. Kenny Perry and Camilo Villegas exchanged places with Perry up to No. 9. Anthony Kim and Lee Westwood remained 11 and 12 this week.
Steve Stricker nearly rallied to beat Mickelson, but ended one shot back partly due to a bogey on the 18th hole. However, he jumped seven places in the world rankings to 13th.
That knocked Ernie Els, Jim Furyk, Justin Rose and Rory McIlroy down one spot apiece. Adam Scott held on to the 18th position, while Mike Weir slid two to 19th.
K.J. Choi shared third at Riviera and moved up two to 20th, while Martin Kaymer slipped two notches to 21st this week.
Amateur Danny Lee became the youngest winner ever on the European Tour when he titled at the Johnnie Walker Classic. The win helped him skyrocket 403 places to No. 159 in the world.