Serena, Sharapova move into Key Biscayne quarters

Serena Williams produced 20 aces and blasted her way into the quarter-finals of the Sony Ericsson Open with a 7-5 6-3 win over Australian Samantha Stosur on Monday.

It was not all plain sailing for Williams, who lost her first serve of the match but came back to grind out the set in the first meeting between the two players since Stosur beat the US player in the 2011 US Open final.

Down 5-2 in the second, Stosur twice saved match point and forced Williams to serve out for the match and although the American trailed 0-40 she booked her spot in the last eight.

Russian Maria Sharapova also booked a place in the quarters with a 6-4 7-6 win over compatriot Ekaterina Makarova despite being broken four times.

Makarova fought particularly hard in the second set but eventually fell 7-3 in the tiebreak.

Sharapova, the runner-up here last year, will face the winner of the match between China's Li Na and German Sabine Lisicki.