Russia's Maria Sharapova continues her return from injury with a second-round win over third seed Victoria Azarenka at the LA Championships.

The former world number one is returning from shoulder surgery, but battled back from a set down to beat Azarenka 6-7 (4-7) 6-4 6-2.

Another former world number one, Ana Ivanovic made hard work of her second-round win over Vania King in Los Angeles.

The sixth-seeded Serb suffered a mid-match slump but rallied to beat American wildcard King 6-4 4-6 6-1.

Seeking her first title since October 2008, Ivanovic struggled with King's relentless counterpunching in the first two sets but in the final set, last year's French Open champion was able to overpower her opponent.

"It's just the first match and I have the ability to improve. I had an opportunity a few times to put the ball away but had a little doubt in my mind as to which shot to take." said Ivanovic.

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