Serena reaches quarters in Beijing

Beijing, China ( - High-flying world No. 1 superstar Serena Williams highlighted Thursday's third-round winners at the $5 million China Open.

The 2004 Beijing champion topped 2005 titlist Maria Kirilenko 7-5, 7-5 on the hardcourts at the National Tennis Center.

Williams is now 8-0 lifetime against the Russian Kirilenko, but she had to work on Thursday.

"I just thought, what else can I do except fight for this point and the next point," Williams said. "Maybe I got lucky a little bit -- I just started to relax and kind of swing and not think about it too much out there. I'm obviously just really happy to get through this match today."

The reigning U.S. and French Open queen Williams is now a brilliant 70-4 this year and seeking her 10th title of 2013. Her quarterfinal opponent on Friday will be sixth-seeded former world No. 1 and 2010 Beijing champ Caroline Wozniacki.

Williams is 5-1 lifetime against Wozniacki

Meanwhile, third-seeded Agnieszka Radwanska routed Slovenian qualifier Polona Hercog 6-0, 6-2 and Wozniacki handled 11th-seeded American Sloane Stephens 6-3, 6-1 on Day 6. Radwanska was the China Open champion two years ago and runner-up in 2009.

In other third-round action, seventh-seeded Angelique Kerber topped 10th- seeded Italian Roberta Vinci 6-2, 6-4, eighth-seeded former world No. 1 Jelena Jankovic destroyed Spaniard Carla Suarez Navarro 6-0, 6-0 in 59 minutes, and Czech Lucie Safarova outlasted German Andrea Petkovic 6-4, 6-7 (4-7), 7-6 (7-2). Jankovic titled here in 2008 and was the Beijing runner-up in 2007. Petkovic was a finalist in 2011.

Friday's other quarters will pit Radwanska against Kerber, fourth-seeded Chinese favorite Li Na versus ninth-seeded Czech slugger Petra Kvitova, and Jankovic against Safarova. Kvitova titled in Tokyo last week by beating Kerber in an all-left-handed final.

The 2013 China Open titlist will collect $860,000.