Agnieszka Radwanska of Poland beat Vera Zvonareva in a three-set thriller to leave the Russian only mathematical chances of reaching the semis at the WTA Championships in Istanbul, Turkey.
Zvonareva, who needed a win in her third and final Red Group game in order to progress, had a great start to match, storming past her rival 6-1 in the opener.
But the Russian failed to maintain her form, and it was all Radwanska in the second set, 6-2.
The third set was extremely tight, with Zvonareva having two match points at 5-3. But it was the Pole who got the vital break to cruise to a 1-6, 6-2, 7-5 victory.
Radwanska now needs to win just one set from Czech Petra Kvitova on Friday to qualify for the semis and send Zvonareva packing.
Meanwhile, Kvitova made sure world No. 1 Caroline Wozniacki is leaving Istanbul after the group stages, beating the Dane in straight sets, 6-4, 6-2.
In the White Group, Belarusian Victoria Azarenka collected her second straight win, making it look easy against China’s Na Li, 6-2, 6-2.
Another Russian player in Turkey, Maria Sharapova, withdrew from the season-ending tournament because of an injury.