The mighty Swiss defeated local favourite 3-6 6-3, 6-1 in the Group A match to make sure he will retain the top-ranked at the end of the year for the fifth time.
Roger Federer defeated Andy Roddick at Wimbledon in Jul 2009 to become the first man to win 15 Grand Slam singles titles.
Apart from this, Federer claimed a larger lead at the ATP World Tour rankings by beating Fernando Verdasco in the first Group A match leaving No 2 Rafael Nadal struggling to make up the gap.
Nadal, on the other hand, has has a disappointing run as he was defeated by Robin Soderling in Group B match on Monday, Nov 23.
The season-ending tournament is being held at the London's O2 Arena.