INDIAN WELLS, California (AP) ― Top-ranked Novak Djokovic reached the fourth round at the BNP Paribas Open on Tuesday when he beat Grigor Dimitrov 7-6 (4), 6-1 for his 20th consecutive victory.

Defending women’s champion Victoria Azarenka extended her own streak despite a nagging right ankle problem, routing Urszula Radwanska 6-3, 6-1 for her 17th straight win. Urszula’s sister, third-seeded Agnieszka Radwanska, was beaten by No. 13 Maria Kirilenko, 6-1, 4-6, 7-5. No. 3 Andy Murray beat Yen-Hsun Lu of Taiwan 6-3, 6-2 in their first meeting in five years, and No. 8 Caroline Wozniacki played the late match against No. 10 Nadia Petrova.

Djokovic trailed 5-3 in the first set when the 21-year-old Bulgarian committed six double faults, including four in one game, to help the Serb force the tiebreaker. Djokovic won it on a backhand error by the youngest player remaining in the draw.

“It was not really a beautiful match to watch,” Djokovic said. “There were a lot of unforced errors, and we both look quite sluggish on the court.”

Dimitrov was broken twice in the second set while falling to 1-17 against top-10 opponents.

“He did all the work making winners and making unforced errors,” Djokovic said. “I just needed to hang in there and try to be patient.”

Djokovic moves on to play Sam Querrey, a 7-6 (5), 6-7 (7), 7-5 winner over Marinko Matosevic.

Djokovic hasn’t lost since Oct. 31, when Querrey beat him at the indoors Paris Masters.

“He does everything really well: unbelievable forehand, unbelievable backhand, moves around the court great, returns great. It’s tough to pick on something,” Querrey said. “I might have to go outside of my comfort zone a little bit and do things I don’t like to do, and hopefully it will pay off for me.”

Maria Sharapova joined Azarenka in the quarterfinals with a 7-5, 6-0 win over Lara Arruabarrena-Vecino of Spain, someone she had never played before.