( CNN ) -- Novak Djokovic and Victoria Azarenka continued their dominance of men 's and women 's tennis by registering straight-sets wins at the Indian Wells Masters in California . The respective Australian Open champions are unbeaten in 2013 , with second-ranked Azarenka on a 17-match winning streak while world No . 1 Djokovic is 15-0 for the year . Djokovic overcame a first-set battle to beat Bulgaria 's Grigor Dimitrov 7-6 ( 7-4 ) 6-1 in the third round . Next up for the 25-year-old top seed is soon-to-be U.S. No . 1 Sam Querrey . `` He started off well today ( Tuesday ) , but then I think he gave me the break with four double faults , '' Serbia 's six-time grand slam champion told the ATP World Tour 's website . `` I have n't done much really in the match in the second set when I made two breaks . It was all of his unforced errors , so I just needed to hang in there and try to be patient . `` I just tried to stay positive and calm and hang in there and wait for the chances . So that 's , I guess , the biggest positive I can take out of today 's performance . '' Querrey will usurp world No . 15 John Isner as the top American male tennis player after a 7-6 ( 7-5 ) 6-7 ( 7-9 ) 7-5 defeat of Australian 23rd seed Marinko Matosevic earned him a last-16 place . `` It means a lot . It 's a great feeling , '' said Querrey , the last player to beat Djokovic in an ATP event , in Paris in November . `` I feel like I have worked hard to earn it . Everyone seems like they 've got their shot with Andy ( Roddick ) and Mardy ( Fish ) and James ( Blake ) and John , and so I feel like it 's my turn now . '' Third seed Andy Murray saved five break points on his way to a 6-3 6-2 victory over Taiwan 's Yen-Hsun Lu , avenging his defeat to the world No . 79 at the Beijing 2008 Olympics . Murray , the 2012 U.S. Open champion , will play Carlos Berlocq in the fourth round after the Argentine upset 16th seed Kei Nishikori . Berlocq 's compatriot Juan Martin del Potro beat unseeded Bjorn Phau 6-2 7-5 to set up a meeting with the German 's veteran compatriot Tommy Haas . In the women 's draw , top seed Azarenka will play former world No . 1 Caroline Wozniacki in the quarterfinals after overcoming an ankle injury to beat Poland 's Urszula Radwanska 6-3 6-1 . `` It was pretty obvious I was n't feeling that well -- my ankle was bothering me , it 's been bothering me for a while , and it has n't really been getting better , '' defending champion Azarenka told the WTA Tour 's official website . `` But on the bright side , I won the match today . I overcame those things and -- I do n't know how -- managed to just take my opportunities and really go for my shots and make it happen , and not just wait for her mistakes . '' Wozniacki dug deep to get the better of Russian 10th seed Nadia Petrova , eventually emerging with a 7-6 ( 7-3 ) 6-3 success . `` Victoria has improved in a few ways that have helped her a lot , '' said the Dane . `` I think I 'm playing well . She 's obviously playing well . I 'm looking forward to playing her again . We 'll see what happens ; I definitely need to bring my A-game . '' Second seed Maria Sharapova , beaten by Azarenka in last year 's final , will play 2012 French Open runner-up Sara Errani in the quarterfinals . Sharapova reached the last eight for a third successive year by beating Lara Arruabarrena-Vecino of Spain 7-5 6-0 . `` I just did n't get a good rhythm on her game from the beginning , '' the Russian said . `` But I thought towards the end of the first and beginning of the second set I really stepped it up , was being more aggressive , and really gave myself a better margin than I did throughout the first set . '' Italy 's Errani won her eighth straight match , beating French ninth seed Marion Bartoli 6-3 6-2 . Fifth seed Petra Kvitova reached the quarterfinals of the event for the first time in her career with a win over fellow Czech Klara Zakopalova . The 2011 Wimbledon champion set up a tie with Russia 's Maria Kirilenko , who shocked Poland 's world No . 4 Agnieszka Radwanska with a 6-1 4-6 7-5 triumph . The remaining quarterfinal pits Australian seventh seed Samantha Stosur against sixth-ranked German Angelique Kerber . Stosur came from behind to defeat another German , 24th seed Mona Barthel , while Kerber -- seeded fourth in the absence of world No . 1 Serena Williams and No . 5 Li Na -- beat Spanish qualifier Garbine Muguruza 6-4 7-5 .
Djokovic and Azarenka both continue winning runs at American Wells . World No . 1 Djokovic wins 15th straight match against Bulgaria 's Grigor Dimitrov . Azarenka 's winning streak now stands at 17 after victory over Urszula Radwanska . John Isner will replace Azarenka as the top-ranked American male tennis player .