London: World number one Novak Djokovic capped a perfect season as he beat six-time champion Roger Federer to win a record fourth straight ATP World Tour Finals title at London's O2 Arena.

The 28-year-old Serb, who lost to Federer in the group stage, broke the Swiss three times to win 6-3, 6-4 in just 80 minutes on Sunday, levelling their record with the 17-time Grand Slam winner at 22-22, Xinhua reported.