Defending champion Andy Murray advanced to the quarter-finals of the Japan Open by beating Lukas Lacko of Slovakia 6-1, 6-2 on Wednesday in Tokyo.

The third-ranked Murray, who finished the match with the roof closed at Ariake Colosseum because of rain, lost only two points in the first five games and even threw in a few drop shots.

The U.S. Open champion and Olympic gold medallist broke Lacko in the third and seventh games of the second set and closed out the match on serve.

"Once I got the break in the second set, I started to play better," Murray said. "I have a couple of days until the next match, so hopefully I can stay in a good rhythm."

Seventh-seeded Stanislas Wawrinka of Switzerland also advanced to the quarter-finals, beating Jeremy Chardy of France 7-6 (1), 6-7 (6), 7-5. Chardy saved three match points in the second-set tiebreaker, but was broken in the 11th game of the final set.

Murray and Wawrinka will meet in the quarterfinals.

"I have had a lot of tough matches with him over the years," Murray said. "He is a good player, especially on the hard court."

Also, third-seeded Janko Tipsarevic of Serbia rallied to beat Gilles Simon of France 4-6, 6-3, 6-1 in the first round, and fourth-seeded Juan Monaco of Argentina defeated Bulgarian qualifier Grigor Dimitrov 6-2, 6-1.

Tipsarevic, ranked ninth in the world, was broken twice in the opening set but bounced back to eliminate the unseeded Simon.

China Open

Two-time champion Novak Djokovic reached the China Open quarter-finals after dismissing Carlos Berlocq of Argentina 6-1, 6-3 on Wednesday in Beijing.

Djokovic rushed through the first set then lost his serve twice in the second before winning the second-round match.

The Serb, champion in 2009 and 2010 in his only previous appearances in Beijing, faces Jurgen Melzer on Friday after the Austrian defeated Alexandr Dolgopolov 7-6 (9), 2-6, 6-1.

Florian Mayer of Germany also made the last eight.

Women's defending champion Agnieszka Radwanska needed more than two hours to put away Spanish qualifier Lourdes Dominguez Lino of Spain 2-6, 6-1, 6-4.

Radwanska, coming off a loss in the final of the Japan Open on Sunday, struggled in her first matchup against the Spaniard. Radwanska broke six times and lost her own serve seven times.

Second-ranked Maria Sharapova downed Sorana Cirstea of Romania 6-2, 6-2, and Slovenian qualifier Polana Hercog rallied from 5-1 down in the third set to beat Ekaterina Makarova 7-6 (5), 3-6, 7-6 (3).

Ana Ivanovic and Jelena Jankovic were knocked out of the third round in straight sets.

Ivanovic was ousted 6-4, 6-3 by Romina Oprandi of Switzerland, who replaced an ill Serena Williams in the draw.

Jankovic fell apart after leading 5-2, going out to Carla Suarez Navarro of Spain 7-5, 6-4.

"Jelena is always difficult to play, but I played well," Suarez Navarro said. "She always fights a lot, and I'm happy to have finished it off."