The back problem that forced Dinara Safina's withdrawal from the Andalucia Tennis Experience is not as bad as first feared, she has revealed.
The former world number one was trailing Victoria Azarenka 5-1 in Marbella when forced to retire.
But after practice the Russian, 24, now feels good enough to play doubles.
"Went to hit with my coach to check my back and it seems OK... So I'll play doubles!!! ," she said on Twitter. "CT and MRI were OK, nothing too serious."
Safina has been struggling with back problems since 2009 and has slipped to 81 in the world rankings.
Top seed Azarenka, who will meet Sara Errani in Saturday's semi-finals after the Italian beat fourth seed Alexandra Dulgheru 6-2 6-2, said: "I feel bad winning in this way, above all against an opponent like Dinara.
"She has been suffering with her injuries for quite a while and I hope she recovers soon."
Second seed Svetlana Kuznetsova beat Lara Arruabarrena 6-1 6-2 and will next face Romanian qualifier Irina-Camelia Begu, who upset sixth seed Klara Zakopalova 6-3 6-3.
At the Family Circle Up in Charleston, United States, world number one Caroline Wozniacki recovered from a break down in the final set to beat Belgian sixth seed Yanina Wickmayer 4-6 6-4 6-4.
In the semi-finals she will play Serbia's Jelena Jankovic who cruised to a straight-sets 6-2 6-0 victory over American Christina McHale.