World No. 1 Serena Williams and sister Venus advanced to the next round while Sabine Lisicki upset eight seeded Eugenie Bouchard at the China Open in Beijing on Tuesday.

Defending champion Serena cruised past Bulgarian qualifier Tsvetana Pironkova in two straight sets 6-2 6-3 to advance into the second round.

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The 18-time Grand Slam champion will next face Czech Republic's Lucie Safarova who also had an easy win against Mona Barthel of Germany 6-3 6-3.

The seven-time majors title holder Venus avenged her first round loss against Caroline Garcia at the recent Wuhan Open as the American defeated the Frenchwoman in two sets 6-4 6-3 in a match that lasted an hour and 14 minutes.

Venus, 34, is set to face the winner of the matchup between Wimbledon champion Petra Kvitova and U.S. Open semifinalist Peng Shuai of China.

Hong Kong Open victor Lisicki was in form against last week's inaugural Wuhan Open finalist Bouchard as the German ousted the Canadian star in straight sets 6-2 6-4.

The 25-year-old Lisicki served out six aces and won 79 percent of her first serves to defeat Bouchard in 74 minutes.

Lisicki will now face another tough challenge in 9^th seed Ana Ivanovic who won over Romina Oprandi of Switzerland 6-4 6-2.

Bouchard, 20, is still in the race for the season-ending WTA Tour Finals on Oct. 17. She is currently in fifth place just 53 points ahead of another fallen player Agnieszka Radwanska of Poland.

Ivanovic, on the other hand, is in seventh place and has a good chance of surpassing the two in the final eight players competing in Singapore. She just needs a strong performance in the tournament.

Yet another contender for the year-ender event is still alive at the tournament. Angelique Kerber  defeated Zarina Diyas of Kazakhstan in straight sets 6-3 6-1 to setup a clash against Svetlana Kuznetsova who won over Kurumi Nara of Japan also 6-3 6-1.

The 26-year-old German is currently in ninth place and still stands a chance to make it in Singapore with a strong performance in the tournament as well at the Kremlin Cup in Moscow.

Tagsserena williams, Venus Williams, Ana Ivanovic, Angelique Kerber