MELBOURNE, Australia — Defending champion Serena Williams had no problems beating Petra Kvitova, 6-2, 6-1, today to move into a third-round match against Carla Suarez Navarro, who ended her sister Venus' run early at the last Australian Open.

Williams converted four of her 11 breakpoint chances against No. 77-ranked Kvitova in a second-round match that lasted 67 minutes, immediately after Venus Williams beat Austria's Sybille Bammer, 6-2, 7-5, on Hisense Arena.

Serena Williams has won the Australian Open every odd-numbered year since 2003, the year she beat older sister Venus in the final.

Venus, in her 10th Australian Open, has won seven Grand Slam singles titles but hasn't gone beyond the fourth round in Australia since '03.

She was upset in the second round last year by Spaniard Suarez Navarro, who beat Andrea Petkovic of Germany, 6-1, 6-4, earlier today.

Ana Ivanovic, the 2008 Australian Open finalist, extended her run of poor results in a second-round 6-7 (6), 7-5, 6-4 loss to Gisela Dulko of Argentina.

"It's hard. It hurts, I must say. For sure it will. But it's a process," said Ivanovic, who slipped from No. 1 to No. 21 and didn't win a tournament in 2009. "I do feel better on the court. I'm playing much better. I feel like my old self. There are still some areas that are not there for me to rely on.

"I just have to sort of keep my head up and try to improve, work."

U.S. Open finalist Caroline Wozniacki of Denmark advanced 6-3, 6-1 over Julia Goerges of Germany and will play No. 29 Shahar Peer of Israel, who beat Tsvetana Pironkova of Bulgaria, 6-1, 6-4.

Among the women advancing were No. 7 Victoria Azarenka of Belarus, No. 9 Vera Zvonareva of Russia, No. 10 Agnieszka Radwanska and No. 16 Li Na of China.

Back on the court where he won his only Grand Slam title, Novak Djokovic overcame an early struggle against Swiss journeyman Marco Chiudinelli before advancing 3-6, 6-1, 6-1, 6-3.

Djokovic had nine double-faults and 52 unforced errors and took a while to get going.

Djokovic will next play Uzbekistan's Denis Istomin, who beat Michael Berrer of Germany, 7-5, 6-3, 6-4.

Sixth-seeded Nikolay Davydenko, who rarely gets onto the center court at this stage of a Grand Slam, had a 6-3, 6-3, 6-0 win over Ukraine qualifier Illya Marchenko in the low-key manner that has typified an 11-match winning streak.

"This court is most special because I won my only Grand Slam here," the 22-year-old Serb said of Rod Laver Arena, where he beat Roger Federer in the semifinals en route to the 2008 title. "It has the nicest possible memories."

Only seven matches into her comeback, Justine Henin held off fifth-ranked Elena Dementieva, 7-5, 7-6 (6), winning the last three points of the tiebreaker to clinch a second-round victory last night. She ended it on her second match point — 24 minutes after she missed her first chance against the Olympic champion.

Henin, who retired in May 2008 while she was ranked No. 1, knows she's capable of reproducing the form that took her to seven major singles titles.

"I lived so much emotion on the court this evening. It was magical," she said. "I was afraid I wouldn't be able to do it, but it was the kind of situation I needed to re-find my confidence."

$22.14 million

Australian Open

At Melbourne Park

Melbourne, Australia

Surface: Hard-Outdoor

Singles

Men

Second Round

Nikolay Davydenko (6), Russia, def. Illya Marchenko, Ukraine, 6-3, 6-3, 6-0. Denis Istomin, Uzbekistan, def. Michael Berrer, Germany, 7-5, 6-3, 6-4. Nicolas Almagro (26), Spain, def. Benjamin Becker, Germany, 6-4, 6-2, 3-6, 4-6, 6-3. Novak Djokovic (3), Serbia, def. Marco Chiudinelli, Switzerland, 3-6, 6-1, 6-1, 6-3. Juan Monaco (30), Argentina, def. Michael Llodra, France, 3-6, 3-6, 7-6 (5), 6-1, 6-3. Alejandro Falla, Colombia, def. Marcel Granollers, Spain, 6-4, 6-1, 6-3.

Marcos Baghdatis, Cyprus, def. David Ferrer (17), Spain, 4-6, 3-6, 7-6 (4), 6-3, 6-1. Mikhail Youzhny (20), Russia, def. Jan Hajek, Czech Republic, 6-2, 6-1, 6-1.

Lukasz Kubot, Poland, def. Santiago Giraldo, Colombia, 6-4, 3-6, 6-3, 6-1. Lleyton Hewitt (22), Australia, def. Donald Young, United States, 7-6 (3), 6-4, 6-1.

Stefan Koubek, Austria, def. Ivan Dodig, Croatia, 7-6 (4), 6-1, 6-2. Tommy Haas (18), Germany, def. Janko Tipsarevic, Serbia, 4-6, 6-4, 6-3, 1-6, 6-3.

Women

Second Round

Agnieszka Radwanska (10), Poland, def. Alla Kudryavtseva, Russia, 6-0, 6-2. Gisela Dulko, Argentina, def. Ana Ivanovic (20), Serbia, 6-7 (6), 7-5, 6-2. Carla Suarez Navarro (32), Spain, def. Andrea Petkovic, Germany, 6-1, 6-4. Victoria Azarenka (7), Belarus, def. Stefanie Voegele, Switzerland, 6-4, 6-0. Li Na (16), China, def. Agnes Szavay, Hungary, 3-6, 7-5, 6-2. Shahar Peer (29), Israel, def. Tsvetana Pironkova, Bulgaria, 6-1, 6-4. Caroline Wozniacki (4), Denmark, def. Julia Goerges, Germany, 6-3, 6-1. Vera Zvonareva (9), Russia, def. Iveta Benesova, Czech Republic, 6-0, 6-3. Sam Stosur (13), Australia, def. Kristina Barrois, Germany, 7-5, 6-3. Francesca Schiavone (17), Italy, def. Julie Coin, France, 6-3, 6-4. Tathiana Garbin, Italy, def. Yaroslava Shvedova, Kazakhstan, 6-7 (5), 6-2, 6-0. Daniela Hantuchova (22), Slovakia, def. Sofia Arvidsson, Sweden, 6-4, 6-1. Venus Williams (6), United States, def. Sybille Bammer, Austria, 6-2, 7-5. Alberta Brianti, Italy, def. Sabine Lisicki (21), Germany, 2-6, 6-4, 6-4. Serena Williams (1), United States, def. Petra Kvitova, Czech Republic, 6-2, 6-1.