On the Tuesday night, in a three-hour and 13-minute match, the third-longest match in WTA Finals history, Wozniacki's marathon training may have actually paid off. She outlasted Maria Sharapova, 7-6(4), 6-7(5), 6-2 in a pulsating, intense match that kept the Singapore audience riveted from start to finish.

The victory put Wozniacki at the top of the White Group and in this round robin tournament gives her a very decent shot of moving on to the semifinals.