PARIS — Novak Djokovic advanced to the Paris Masters quarterfinals when Damir Dzumhur retired trailing 6-1, 2-1 on Thursday.
Dzumhur had a lengthy massage on his lower back late in the first set and got loud applause when he carried on playing, but after a few more games, he stopped for good. Djokovic was in total control and did not face a break point, breaking Dzumhur's serve three times.
Djokovic, who will reclaim the No. 1 ranking next week regardless of where he finishes, faces Marin Cilic in the quarterfinals.
''I'm obviously very proud of the achievement,'' said Djokovic, whose ranking slipped to No.