Russia’s Maria Sharapova advanced to semifinals of the WTA Championships in Istanbul after coming back from a set down to beat Agnieszka Radwanska in a three-hour battle.
World No. 2 Sharapova won 5-7, 7-5, 7-5 to join Serena Williams in the semis of the $4.9 million season-ending event after overcoming Italy's Sara Errani in her opener.
"I'm happy to get to that stage - the goal is always to get out of your group," Sharapova said after the match.
"I was injured last year and didn't play very well, so to be in the semifinals this year makes me very proud, and especially given the way I fought tonight."
Radwanska, playing in her second WTA Championships, grabbed the first set with a late break.
But Sharapova, the 2004 champion, surged back to make decisive breaks with the score at 5-5 in the next two sets, finishing off her opponent with her seventh ace of the match.
The 25-year-old Russian showed the greater aggression with 66 winners and 64 unforced errors, while Radwanska notched up just 18 winners and 19 errors.
"It was a very physical match with so many ups and downs - I wasn't playing my best tennis, but I kept fighting," Sharapova said adding that she is now motivated more than ever.
"And when you win when you're not at your best, it gives you extra motivation to do better in the next one."
Sharapova is now at the top of the white group and yet to face Australia’s Sam Stosur, who replaced the ill Petra Kvitova.
Radwanska must beat Errani to make sure of staying in the competition.
Elsewhere, world No. 1 Victoria Azarenka survived scare to beat Germany’s Angelique Kerber in another three-hour thriller (11)6-7, 7-6(2), 6-4.
The German left-hander had to save five set points before winning the first set.
Azarenka made an early break in the second set but later had to survive two match points to win it on a tie-break, before finishing off Kerber in the third.
"I was fighting so hard - at the beginning of the tournament it's quite hard to have a match like that," the Belarusian star said.
"But all the best players are here and you have to show your best tennis. I don't think I did that, but at least I showed my best fight."
Azarenka next plays China’s Li Na and Williams.