- Serena Williams into the quarterfinals of WTA tournament in Miami
- Williams avenges 2011 U.S. Open defeat to Samantha Stosur
- World No. 1 Victoria Azarenka fights back to extend 2012 run to 26-0
- Venus Williams, Maria Sharapova, Caroline Wozniacki, Li Na also progress
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 couldn'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 wasn'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.