Top seed Serena Williams breezed into the quarter-finals of the Medibank International in Sydney with a straight-sets triumph over world number 25 Maria Jose Martinez Sanchez. Williams showed no signs of the early-season rust that has plagued many of her main rivals in the early rounds, clinching a 6-1 6-2 victory. It was a good workout, Williams said. It was definitely getting hotter the longer I stayed out, so I needed that. I need to play in the heat as much as I can. The American will face Vera Dushevina in the next round after the Russian defeated fellow countrywoman Elena Vesnina 6-3 6-4 to progress to the last eight. Meanwhile, third seed Svetlana Kuznetsova became the latest big-name casualty to bow out of the tournament after losing in straight sets, 7-5 6-2, to Slovakia's Dominika Cibulkova.Earlier, world number two Dinara Safina overcame a slow start before posting a hard-fought 7-5 6-4 victory over Poland's Agnieszka Radwanska.She will next face fifth seed Elena Dementieva, who defeated Daniela Hantuchova 6-2 4-6 6-2, in the quarter-finals.Flavia Pennetta completed the women's singles programme for the day with a 6-2 7-6 (7-4) win over China's Na Li.In the men's tournament, there was a big upset when fifth seed Sam Querrey crashed to a 6-2 5-7 6-4 defeat against Russian world number 52 Evgeny Korolev.There was better news for the other seeds in action, with Benjamin Becker (eighth) cruising into the second round with a comfortable 6-3 6-3 victory over Argentinian qualifier Juan Ignacio Chela and Viktor Troicki (sixth) advancing with a 7-6 (7-5) 6-4 win over Florent Serra.
