Serena Williams avenges U.S. Open final loss to Stosur with Miami win March 26, 2012 -- Updated 2037 GMT (0437 HKT) Serena Williams enjoyed her victory over Australian Samantha Stosur in Miami. Serena Williams into quarterfinals of WTA tournament in Miami Williams avenges 2011 U.S. Open defeat to Samantha Stosur Maria Sharapova beats fellow Russian Ekaterina Makarova Venus Williams playing Ana Ivanovic in night session (CNN) -- Serena Williams avenged her 2011 U.S. Open final defeat to Samantha Stosur with a straight sets win over the Australian sixth seed in 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. Williams converted four of 13 break point opportunities to go 5-3 career against Stosur. 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 top-ranked Victoria Azarenka in the final of the Australian Open, also saw off Makarova in straight sets in Melbourne. But she did not have things all her own way against a dogged opponent and was taken to a second set tiebreak before sealing her passage. Seventh seed Marion Bartoli of France beat another Russian, Maria Kirilenko, 6-1 6-2 in an early match Monday. Serena's sister Venus was in action in the night session against former French Open champion Ana Ivanovic in their last 15 match.