Roger Federer is guaranteed to end the year as world number one after winning his 11th title of 2005 at the Thailand Open.

The Swiss, winner of the U.S. Open and Wimbledon, has 1,245 points in the ATP Champions Race and cannot be caught by Spain's Rafael Nadal, the French Open champion, who is in second place with 853 points.

Last year Federer sealed the year-end number one spot in mid-September.

Federer's 2005 record is 77-3 and his last defeat was by Nadal in the French Open semi-finals on June 3. He has won his last 24 finals, beating Britain's Andrew Murray 6-3, 7-5 in the Bangkok final on Sunday.