It works like this.......Westwood overtook Woods to go Top of the rankings on Sunday evening as the rankings are updated monthly,so the past months golf count not just one tournament.
Because Kaymer was playing he could have leapfrogged both with a win,but did't win and stays third.
Isn't it more due to the fact that Woods has lost a lot of ranking points because results from two years (or so) ago no longer count.
If I recall they did say after the Ryder Cup that if Westwood didn't play for two weeks he would have been #1 then. But because he played the following week (and didn't win), it delayed him becoming #1.