Novak Djokovic capped a remarkable season with victory over Roger Federer to claim a record fourth straight ATP World Tour Finals title.

The world number one from Serbia broke serve three times to win 6-3 6-4 in 80 minutes at London's O2 Arena. He ends the year with 11 titles including three Grand Slams, taking his total to 10 majors.

Aside from the trophy, another 1,300 ranking points and the cheque for £1.4m, Djokovic also draws level with Federer at 22-22 in career meetings.