Novak Djokovic only needed a set. The Serb No. 1 rarely settles for less than two, though, especially against one of his favorite opponents.
Djokovic reached the semifinals of the ATP World Tour Finals by extending his dominance over Tomas Berdych, beating the Czech player 6-3, 7-5 on Thursday in their last round-robin match and stay on course for a fourth straight title.
Earlier, Roger Federer overcame a stubborn Kei Nishikori to finish the round-robin stage unbeaten and claim first place in the group.
Under the tournament's tiebreaker rules, Djokovic would have advanced even if he lost in three sets, which would have left both players with a 1-2 record. That meant...