Defending champ Azarenka, Rafael Nadal move into 4th round at Australian Open

Rafael Nadal, of Spain, celebrates his win over Gael Monfils, of France, during their third round match at the Australian Open tennis championship in Melbourne, Australia on Jan. 18, 2014. (AP Photo/Eugene Hoshiko)

MELBOURNE, Australia -- Top-seeded Rafael Nadal and two-time defending champion Victoria Azarenka looked as if they were in a hurry to get out for late dinners Saturday while posting straight-set victories in their night matches at the Australian Open.

Nadal continued his dominance of Gael Monfils, beating the Frenchman for the 10th time in 12 matches in a 6-1, 6-2, 6-3 victory in just over two hours to advance to a fourth-round match against Kei Nishikori.

The left-handed Spaniard didn't play here last year during a seven-month injury layoff, and said he was pleased to be back on a night session at Rod Laver Arena.

"It's very emotional for me to have the chance to be back here after missing last year," Nadal said. "I think this is my best match of the tournament so far."

Azarenka was equally as dominating in beating Yvonne Meusburger 6-1, 6-0 in exactly an hour.

Azarenka will play American Sloane Stephens in the next round in the reprise of an acrimonious semifinal here when Azarenka took a questionable medical timeout that turned the match in her favour.

"We left it all last year here," Azarenka said when asked about the rematch.

Earlier, the girlfriend and boyfriend pair of Maria Sharapova and Grigor Dimitrov both advanced along with Wimbledon champion Andy Murray and 17-time Grand Slam winner Roger Federer.

And finally, the oppressive heat wave of the past four days gave way to more benign conditions.

Sharapova, who endured the worst of the torrid heat in her second-round match, beat Alize Cornet 6-1, 7-6 (6) to reach the fourth round. The match was played in high humidity but in temperatures of about 22 Celsius (72 Fahrenheit), considerably cooler than the scorching 42 C (108 F) conditions she endured for 3 hours, 28 minutes on Thursday.

Dimitrov reached the second week at a major for the first time when he converted his fifth match point to beat No. 11-seeded Milos Raonic of Canada 6-3, 3-6, 6-4, 7-6 (10).

The 22-year-old Bulgarian is considered one of the up-and-coming players on the men's tour, as is Raonic. At the end of the match, the two hugged like old mates at the net.

"I think it's a great stepping stone for me to get into that second week," Dimitrov said.

Federer had a 6-2, 6-2, 6-3 win over Teymuraz Gabashvili, and three-time finalist Murray reached the fourth round for the sixth straight year with a 7-6 (2), 6-4, 6-2 win over No. 26-seeded Feliciano Lopez.

Elsewhere, 2008 finalist Jo-Wilfried Tsonga beat fellow Frenchman Gilles Simon 7-6 (5), 6-4, 6-2 and No. 16 Nishikori beat Donald Young, the last American man in the singles draw, 7-5, 6-1, 6-0.

Tsonga next plays Federer, who is No. 6 at this Australian Open, his lowest seeding in more than a decade, after a year in which he didn't reach a Grand Slam final for the first time since 2002.

Last year, Federer beat Tsonga in the quarterfinals here.

"For me it's going to be the possibility to have revenge," Tsonga said.

Murray, playing only his second tournament since minor back surgery in September, only dropped one service game in a 2-hour, 15-minute match and next faces Stefane Robert, a lucky loser from qualifying, who is into the fourth round for the first time after beating Martin Klizan.

"It's been a good start," Murray said. "It was very tricky the first couple of matches with the heat, but today was beautiful to play in."

Sharapova will next play Dominika Cibulkova, who beat No. 16 Carla Suarez Navarro 6-1, 6-0. Former No. 1-ranked Jelena Jankovic had a 6-4,7-5 win over Kurumi Nara, her third consecutive victory over a Japanese player.

Fifth-seeded Agnieszka Radwanska had a 5-7, 6-2, 6-2 over No. 29 Anastasia Pavlyuchenkova and will next play Garbine Muguruza of Spain, who ousted former No. 1-ranked Caroline Wozniacki 4-6, 7-5, 6-3.

Stephens, who had an upset win over Serena Williams in the quarterfinals here last year, reached the fourth round at a fifth consecutive major with a 7-5, 6-4 win over Elina Svitolina.

Williams will play her fourth-round match Sunday against 2008 French Open champion Ana Ivanovic. Three-time defending champion Novak Djokovic plays Fabio Fognini in an afternoon match on Rod Laver Arena.