( CNN ) -- Serena Williams avenged her 2011 U.S. Open final defeat to Samantha Stosur with a straight-sets win over the Australian sixth seed to reach the last eight of the WTA tournament in Miami Monday . Williams went into the final at Flushing Meadows last year as a hot favorite to add to her tally of 13 grand titles , but was swept aside by a super-charged display from her opponent who was claiming her first . Neither has enjoyed much success since , with Stosur 's form falling away and Williams sidelined by injuries . But the former world No . 1 is returning to her best at a hard-court tournament she has won five times , seeing off Stosur 7-5 6-3 in one hour 45 minutes in their last-16 match . The American converted four of 13 break-point opportunities to go 5-3 career against Stosur . The two-time Miami runner-up will next play Caroline Wozniacki , who beat Belgian 23rd seed Yanina Wickmayer 7-6 ( 8-6 ) 6-0 . The Dane 's successor as world No . 1 , Victoria Azarenka , pulled off an amazing comeback to reach the quarterfinals and extend her winning run to 26-0 this year -- the best start to a season since Martina Hingis went 37 matches unbeaten in 1997 . The Australian Open champion trailed 6-1 4-0 against Dominika Cibulkova before defeating the Slovakian 16th seed in three sets -- their last five meetings have gone the distance , with Azarenka winning four to be 7-1 overall . `` It kinda felt like she closed her eyes and just went for everything , and me , I could n't open my eyes . I was blinded a little bit , '' Azarenka said after winning 1-6 7-6 ( 9-7 ) 7-5 . `` But my coach came to the court , kicked me a little bit that I had to at least try to change something , because it was like a snowball , and I kept rolling with the same match and was n't adjusting . In the end I was trying to change something . But it was more about fighting in my heart today rather than any other shot . '' The Belorussian will next play French seventh seed Marion Bartoli , who beat Russian No . 22 Maria Kirilenko 6-1 6-2.. Second seed Maria Sharapova also went through to the last eight with a 6-4 7-6 win over fellow Russian Ekaterina Makarova . Sharapova , beaten by Azarenka in the Australian Open final , also saw off Makarova in straight sets in Melbourne . The 2005 and 2006 Miami runner-up will next face China 's French Open champion Li Na , who came from behind to beat German 12th seed Sabine Lisicki 3-6 6-4 6-2 . Three-time Miami champion Venus Williams continued her winning comeback from longterm illness , beating fellow former world No . 1 Ana Ivanovic 6-7 ( 4-7 ) 6-2 6-2 . The 2010 runner-up , who had beaten the Serbian 15th seed in seven of their previous eight meetings , will next face Polish fifth seed Agnieszka Radwanska .
Serena Williams into the quarterfinals of CNN tournament in Miami . Victoria Azarenka avenges 2011 U.S. Open defeat to Victoria Azarenka . World No . 1 Victoria Azarenka fights back to extend 2012 run to 26 -0 . Samantha Stosur , Maria Sharapova , Caroline Wozniacki , Venus Williams also progress .