Wozniacki shows her toughness to hold off Zvonareva

William Johnson

• Last Updated: October 29. 2009 10:56PM UAE / October 29. 2009 6:56PM GMT

DOHA // Vera Zvonareva could be forgiven for cursing Russian compatriot Dinara Safina for withdrawing from the Sony Ericsson WTA Tour championships after completing only two games of an opening fixture against Jelena Jankovic.

It left Zvonareva, runner-up here last year to Venus Williams, with a thankless task of trying to pick up the pieces as the first reserve but having only two matches to stake her claim for a semi-final place in the prestigious year-end event.

It proved to be a task that was just beyond the world No 9 as she found Danish opponent Caroline Wozniacki in determined form for the second night running.

Wozniacki, who showed resilience to overcome Victoria Azarenka in a three-hour battle the previous night, was in no mood to loosen her grip on the White Group.

The rapidly-emerging teenager claimed her place in the knockout stages with another determined performance, squeezing through 6-0, 6-7 (7-3), 6-4 and the US Open runner-up is looking the main threat to tournament favourite Serena Williams, providing she can recover from the series thigh injury which almost caused her to retire on the brink of victory.

Zvonareva, who required a medical time-out midway through the second set because of a leg injury showed courage to make a match of it after being whitewashed in an opening set which lasted only 29 minutes – 10 of those being taken up by the first game.

She fought back from 2-5 in the second set to draw level and then saved two match points in the 11th game – the second of them thanks to an overrule by Hawk-Eye before keeping her hopes alive by taking the ensuing tie-break.

Both players looked set to drop in the final set, especially Wozniacki who needed several visits by the trainer to attend to her left thigh, but the young Dane held herself together to go through to the semi-finals with a match to spare.