Wozniacki to end year top of the world

Russian Sharapova, who began the day as the only player still able to topple Wozniacki from the top of the rankings, quit after losing 7-6 6-4 to China’s Li Na, her second round-robin defeat at the tournament.

The 21-year-old Dane could have clinched the accolade for the second consecutive year with victory over Vera Zvonareva in the Sinan Erdem Dome later in the day but she lost 6-2 4-6 6-3, and Sharapova’s withdrawal has already settled the issue.

“The ankle didn’t recover as well as I had hoped after my first match,” said Sharapova who lost to Samantha Stosur on Tuesday. “It limits my movement a lot and it’s not something I really want to risk. I tried to push it as much as I could but I think it was a little too soon.”

Sharapova injured her ankle in Tokyo recently and only just recovered in time to compete in Istanbul. She will be replaced by first alternate Marion Bartoli of France who will face Victoria Azarenka on Friday.

Meanwhile, Laura Robson got the better of Heather Watson in a three-set battle as the British teenagers went head to head for the first time in their careers yesterday. Robson recovered from a mid-match slump to beat Watson 6-1 3-6 6-3 at the AEGON GB Pro-Series tournament in Barnstaple, held at the Tarka Tennis Centre in the Devon town.

Guernsey player Watson, 19, has already broken through to the world’s top 100 players and currently stands 87th, while London-based 17-year-old Robson is ranked 135th.

Robson looked like winning easily at the indoor tournament when she claimed an early break of serve to lead 2-0 in the second set, but Watson fought back to force a decider. Robson broke serve decisively to move 4-2 in front, and held her serve from there to complete victory in the second-round match.

“I’m sure we’re going to play a fair few times in the future,” said Robson. “It was a tough match and I’m really glad to get through.”