Ian Poulter charged from well back Sunday and won the WGC event, moving from 26th to No. 15 in the rankings. Dufner tied for second and Oosthuizen was tied for sixth in the tournament.
That boosts Dufner from 10th to No. 7 in the rankings while Oosthuizen returns to the Top 10 at No. 10. Masters champion Bubba Watson, 33rd at the WGC tournament, falls one place to 11th in the rankings.
Some tournaments are on both the PGA and European PGA schedules this year. One of those is the European Tour's DP World Tour Championship, an $8 million event in the United Arab Emirates.
The fourth spot is taken by Lee Westwood with a ranking points average of 6.707 and the rankings begin to bunch up after that.
Justin Rose, whose average is 6.257, is fifth, with Adam Scott in sixth but close behind at 6.097. Dufner's average is 5.990 and he pushes Webb Simpson down a spot to eighth at 5.801. Brandt Snedeker comes in ninth at 5.768 and Oosthuizen's average is 5.717. Watson has an average of 5.679.