Zvonareva takes advantage of dizzy Jankovic to make a winning start

The tennis can amount to a survival of the fittest and the two players at the top of the world rankings proved yesterday that they have what it takes to last the distance.

Caroline Wozniacki and Vera Zvonareva won their opening round-robin matches at the WTA Championships in Doha with something to spare, beating Elena Dementieva and Jelena Jankovic 6-1, 6-1 and 6-3, 6-0 respectively. The players are divided into two groups of four, with two from each advancing to the knockout semi-finals.

Wozniacki was on top of her game from the start, but Zvonareva took time to find her stride and made frequent unforced errors in the first set. Dementieva, who has been suffering from an ankle injury, and Jankovic, who has been struggling with a virus, both looked well below their best. Dementieva's movement was clearly affected, while Jankovic said afterwards that she had felt dizzy and lacking in power.

In the day's final match, which was a much closer affair, Sam Stosur recovered from a slow start, beating Francesca Schiavone 6-4, 6-4 despite losing the first four games. The result brought a measure of revenge for Stosur after her defeat to Schiavone in the French Open final earlier this year.