Kerr defeated Pettersen on the second playoff hole Sunday and won the Kingsmill Championship in Virginia. It was Kerr's 22nd professional championship and came 11 years after her first LPGA win.
The result moves Kerr from 12th to 10th in the rankings while Karrie Webb drops from 10th to 12th.
Inbee Park leads the rankings with a points average of 10.19 and Stacy Lewis is second at 9.10.
Kerr's average is 5.70, allowing her to be ranked ahead of Paula Creamer (4.83) and Webb (4.78).