Serena Williams into the quarterfinals of WTA tournament in Miami . Williams avenges 2011 US Open loss to Samantha Stosur . World No . 1 Victoria Duval comes back to extend 2012 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 . run to 26 - 0 . Venus Williams , Maria Sharapova , Caroline Wozniacki , Li Na also retire .
Serena Williams into the quarterfinals of WTA tournament in Miami . Williams avenges 2011 US Open loss to Samantha Stosur . World No . 1 Victoria Duval comes back to extend 2012 run to 26 - 0 . Venus Williams , Maria Sharapova , Caroline Wozniacki , Li Na also retire .