After Federer's 7-5, 4-6, 6-4 win earlier in the day, world number one Djokovic knew he would advance to the last four if he could secure one set against Berdych in his concluding group match at London's O2 Arena.
The Serb, a winner of three Grand Slam titles this year, wasted little time achieving that goal as he took the first set to ensure he would finish second in the group behind Federer and eventually eased to victory in 89 minutes.
Djokovic's bid to win the Tour Finals for a record fourth successive year is likely to face a sterner test tomorrow from his old rival Nadal who looked in fine form while romping to victories over Stan Wawrinka and Andy Murray to secure top spot in the other group.
Federer, who has won the Tour Finals a record six times will face either Murray or Wawrinka who clash today in the semi-finals.
Losing to Federer in straight sets would never be an easy result to stomach for the ultra-competitive Serb, but it was especially painful since it ruined his three remarkable winning streaks.

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