Roger Federer beat Britain's Andy Murray in three sets at the ATP world Tour finals to guarantee finishing the season as the world number one. The Swiss won the Group A round-robin match 3-6, 6-3, 6-1 in one hour and 57 minutes before a capacity crowd of 17,500 at London's 02 Arena. Yesterday's win earned Federer enough ranking points to ensure he cannot be overtaken by Spain's Rafael Nadal at the season-ending tournament of the world's top players in the British capital