He gained the decisive break early in the second set when Ljubicic sent a backhand sailing wide.
Azarenka said she altered her approach in the second set and became more aggressive.
Stosur took a 3-0 lead in the second set and held the rest of the way.
"She had more firepower and really started firing, especially in the second set, " said the Scot.
Nadal did not let up in the second set, and perhaps even stepped up a gear.
And the Argentine was in great form as he broke four times in the second set.
Serving at 4-5 in the second set, she erased three set points and held.
Maybe in the second set at 5-5, 15 30 but he served really well all match.
In the second set, he fell behind 5-3, recovered and then lost a tiebreaker.
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When she first injured her ankle, Li was trailing 3-1 in the second set.
Once I got the break in the second set, I started to play better.
"I lost faith in my game and my repertoire of shots in the second set, " said Corretja.
They appeared to be coasting toward victory in the second set, too, until Kessy remembered her gum.
Sharapova had 57 unforced errors, including 13 double-faults, and overcame three set points in the second set.
Clijsters' breakthrough in the second set came after breaking Wozniacki to lead 4-2 and take the next game.
Then after going a break down in the second set Williams recovered again to close out the match.
Italy's Errani refused to capitulate in the second set, but was never able to threaten the Russian's dominance.
Rubin had a chance to close out her match against Schwartz at 40-0, 5-1 in the second set.
Tsonga looked to have restored confidence in the second set until Klizan restored his advantage in the third.
But the turning point proved to be the first time Baltacha lost her serve in the second set.
Hantuchova's resolve seemed to fizzle out after that and two breaks in the second set secured Clijsters' victory.
The world number three then twice broke his opponent's serve in the second set for an ultimately comfortable victory.
Sharapova found herself trailing 4-1 in the second set after the incorrect call.
Grandin, the world number 203, took a 2-0 lead in the second set before Golovin turned around the contest.
The Dane had to come back from 3-1 down in the second set and 3-0 adrift in the decider.
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When Venus did have a chance to tighten things in the second set, Serena made sure it didn't happen.
In the second set, Nadal maintained the pressure and broke to lead 3-1.
Venus won two points on Serena's serve trailing 3-2 in the second set.
When time ran out, and Kallasvuo had to get to work, he was up 3--2 in the second set.
But I was fortunate enough to win that first set and get back into it in the second set.
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