Tiger Woods held on to the top spot and padded his cushion over No. 2 Vijay Singh.
Mickelson, who birdied the 72nd hole to win the PGA Championship, jumped ahead of Ernie Els. Els, who is out for the year with a knee injury, slipped to fourth.
Retief Goosen, Sergio Garcia, Adam Scott and Padraig Harrington followed Els. Former PGA champion David Toms climbed two spaces to ninth in this week's rankings.
Jim Furyk and Kenny Perry each dropped one notch to 10th and 11th, respectively. Perry was followed by Angel Cabrera and Chris DiMarco.
Davis Love III, who shared fourth place with Woods behind Mickelson at the conclusion of the PGA, climbed four spots to No. 14. Darren Clarke, Luke Donald, Tim Clark and Fred Couples each slipped one spot this week and occupy spots 15-18.
Michael Campbell and Stewart Cink exchanged positions from a week ago, with the U.S. Open winner moving to 19 with Cink slipping to 20.