Azarenka books place in Miami Open third round after Keys retires hurt

Victoria Azarenka is through to the third round of the Miami Open after US Open finalist Madison Keys was forced to retire with a leg injury.

Belarusian Azarenka is a three-time winner of the tournament and was up by a set and a break when Keys ended the second-round match.

The first set went into a tiebreak after the world number 186 failed to capitalise on two set points when serving for the match, but she prevailed on a tie-break which featured nine breaks across the 12 points.

Azarenka will play Anastasija Sevastova after the Latvian beat Alize Cornet of France 7-5 6-4.

World number one Simona Halep dropped the first set but went on to beat Oceane Dodin 3-6 6-3 7-5 and she will face Agnieszka Radwanska, who prevailed 6-3 7-6 (7/4) against Alison Van Uytvanck.

Other seeds through to the third round include Garbine Muguruza, whose opponent Amanda Anisimova withdrew, and Karolina Pliskova, who prevailed 7-5 7-5 against Ekaterina Makarova.

Reigning US Open champion Sloane Stephens is also through to the next round, where she will face qualifier Monica Niculescu after she beat Ajla Tomljanovic 6-1 6-3.