ISTANBUL (AFP) ― Maria Sharapova’s season ended in disappointment on Wednesday as she saw her hopes of regaining the title at the WTA Championships after a seven year gap and of dethroning Caroline Wozniacki as world No. 1 dashed because she is still feeling the effects of an ankle injury.

The former Wimbledon, U.S. Open and Australian Open champion from Russia announced that she was withdrawing from the women’s tour’s flagship event after losing 7-6 (4), 6-4 to Li Na, the French Open champion from China.

Her decision ensured that Denmark’s Caroline Wozniacki would become year-end world number one for the second successive year.

However, the Dane was unable to celebrate that with a victory as she was beaten 6-2, 4-6, 6-3 by Vera Zvonareva, the Russian who finished last year in second place, although this result decides nothing.

Provided Wozniacki beats Wimbledon champion Petra Kvitova on Thursday, she will finish the group with two wins and with a decent chance of qualifying for the semifinals.

Sharapova could still feel the ankle injury she sustained four weeks ago in Tokyo, despite a very spirited effort in a flawed but fine match against a revitalized Li.

She always sought to take the initiative from the hard-hitting Sharapova, and her boldness contributed to her first win since August.

It was also only Li’s seventh since making history in Paris in June by becoming the first Chinese player to win a Grand Slam singles title.

Sharapova had points for a double break of serve and a 5-2 lead in the first set, and then led 4-0 in the tie-break, before Li fought back brilliantly.

In the second set Sharapova trailed by two breaks but battled back to earn three points for a double break back at 5-5 before Li denied her and took the match.

Sharapova said that two matches in as many days had tested her ankle to the limit.

“But the ankle didn’t recover as well as I hoped after the first match,” Sharapova said, referring to her loss on Tuesday to Samantha Stosur, the French Open champion from Australia.

“The swelling got a little worse, and it limits my movement a lot. Knowing that I have some time (in the close season) to recover I would rather do that than risk damaging something else.”

It means that Sharapova will not play her last group match on Friday against Victoria Azarenka, and that Marion Bartoli of France will take part in the tournament.

That though may depend on there being no other withdrawals.

The result was a big blow to the $5 million tournament, which lost its highest profile player, but a welcome consolation was the partial return to form of Li, who has had long lasting knee problems.

Despite their respective ailments both players played some dramatic, full-blooded rallies with both summoning imagination, courage, and great resolve to recover from deficits.

“It was the first match I won for so long ― I am so happy I can win this,” Li said.

“Because it was the first match I was a little nervous, and also because I really wanted to win it. Neither of us was a hundred percent but I think both of us played at a high level.”

Li admitted that her confidence had taken a bit of a dive since her moment of glory in Paris.

“Of course it’s a little bit different from the French Open, but you know this is sport. This is tennis. You have to win, you have to lose,” she said.

Nevertheless she looked very pleased to win, and if she wins again against Azarenka on Thursday, she will have a good chance of qualifying for the semifinals.

Azarenka, who won the title in Luxembourg last week, again showed herself in good form, by earlier outplaying Stosur 6-2, 6-2, and maintained her one hundred percent winning record against the Australian.