Switzerland's Roger Federer serves during the singles final against Serbia's Novak Djokovic on the eighth day of the ATP World Tour Finals tennis tournament in London.

Djokovic returns during the singles final against Federer on the eighth day of the ATP World Tour Finals tennis.

Federer returns against Serbia's Novak Djokovic on the eighth day of the ATP World Tour Finals tennis tournament in London.

Djokovic dives for a return against Switzerland's Roger Federer during the singles final on the eighth day of the ATP World Tour Finals tennis tournament in London.

Djokovic hits the ground after diving for a return.

Federer serves against Serbia's Novak Djokovic during the singles final on the eighth day of the ATP World Tour Finals tennis tournament.

Djokovic serves against Switzerland's Roger Federer during the singles final on the eighth day of the ATP World Tour Finals tennis.

Djokovic poses with the winners' trophy after the singles final against Switzerland's Roger Federer on the eighth day of the ATP World Tour Finals tennis tournament.

Novak Djokovic produced a masterful display to end Roger Federer’s reign as ATP Tour Finals champion as the world number one swept to a 7-6 (8/6), 7-5 victory in the final on Monday

Federer poses with the runners-up shield after being beaten by Serbia's Novak Djokovic in the singles final against on the eighth day of the ATP World Tour Finals tennis tournament in London.