Williams sisters in quarters

Wimbledon champion Serena needed a second set tie-break to overcome Hungary's Melinda Czink 6-3, 7-6, while big sister Venus advanced with a 6-1, 7-5 win over Russia's Alla Kudryavtseva.

Top seed Serena struggled to master left-handed Czink's fierce forehand but the American's greater experience proved vital, especially in staving off a set point with a clever serve when the Hungarian led 7-6 in the tie-break.

The world number 56 then missed two forehands to hand Serena the set and the match.
Stosur held match points against the American in Sydney earlier this year and watched her opponent from the stands on Thursday.

Venus faced less of a struggle than her younger sister, but was tested in the second set against the hard-hitting Kudryavtseva.

Next up for the seven-time Grand Slam champion is a mouth-watering clash against Maria Sharapova, who is continuing her rehabilitation from a long injury lay-off. The Russian leads their rivalry 3-2.

In other matches, fourth-seeded Jelena Jankovic was pushed hard by German teenage prospect Sabine Lisicki before emerging with a 2-6, 6-2, 6-4 victory.

The Serb advanced to a meeting with eighth-seeded Marion Bartoli of France after last year's losing finalist beat American teenager Melanie Oudin 7-5, 6-4.

Kunitsyn stunned

In Los Angeles, Argentina's Leonardo Mayer pulled off the third upset of seeded players at this week's men’s LA Open, eliminating fifth-ranked Russian Igor Kunitsyn 7-6, 6-7, 6-3 in the second round on Thursday.

Seventh-seeded German Benjamin Becker and third seed Dmitry Tursunov of Russia had been knocked out earlier in the week. Mayer squandered a 5-2 lead in the second set, his opponent fighting back to clinch the tie-break 9-7, before wrapping up the third to seal victory in two hours, 43 minutes at the LA Tennis Center.

The 22-year-old Argentine will next face second-seeded Mardy Fish, who survived a few anxious moments before scraping past Australian wildcard Chris Guccione 6-7, 7-6, 6-4.
In other matches, fourth-seeded Israeli Dudi Sela shrugged off the loss of the second set to beat American Robert Kendrick 6-4, 3-6, 6-1 and Sam Querrey held off a spirited fightback by fellow-American Ryan Sweeting to win 6-3, 6-7, 6-3.

Sela, who helped his country beat Russia earlier this month to reach the Davis Cup semifinals for the first time, will face world number 32 Querrey in the last eight, the big-serving American having beaten qualifier Sweeting in just under two hours.

Reuters