Victoria Azarenka reaches quarterfinals in Brisbane

BRISBANE, Australia -- After two injury-interrupted seasons, Victoria Azarenka is emerging from the shadows of some highly ranked rivals who have either withdrawn from Australian Open warm-up events or lost in the early rounds.

The two-time Australian Open champion reached the quarterfinals of the Brisbane International -- a tournament she won in 2009 -- with a 6-3, 6-2 win over Ysaline Bonaventure on Wednesday.

Bonaventure, a lucky loser from qualifying, was cast into the second round as a replacement for top-seeded Simona Halep, who had a bye before withdrawing Tuesday from a scheduled second-round match with Azarenka because of an Achilles tendon problem.

The No. 2-ranked Halep withdrew within an hour of defending champion Maria Sharapova pulling out of the tournament with a left forearm injury. Top-ranked Serena Williams skipped her first Hopman Cup match in Perth and then retired in the second set of the U.S. team's second match, citing inflammation in her left knee.

Venus Williams and Ana Ivanovic -- the top two seeds at the ASB Classic in Auckland, New Zealand -- were beaten in the first round.

Azarenka conceded an early service break against Bonaventure and had seven double-faults in the first set but otherwise dominated after converting her fifth break-point chance in a fourth game that lasted more than 17 minutes and went to deuce 11 times.

Azarenka, who dropped to a year-end No. 22 ranking in December after being restricted to just 23 events across 2014 and '15, is working her way back into form.

"I definitely missed playing since I haven't in a while," she said. As for the broader issue of injuries, she said: "I'm just going to try to take care of myself right now, and hopefully everybody will be ready for the Australian Open."

Fourth-seeded Angelique Kerber beat Madison Brengle 6-3, 6-0 to set up a meeting with Anastasia Pavlyuchenkova, while Andrea Petkovic had a 7-5, 6-4 win over Ekaterina Makarova to move into a quarterfinal against U.S. qualifier Samantha Crawford, who had an upset 7-5, 7-5 win over seventh-seeded Belinda Bencic.

Petkovic, who has struggled in the past with serious injuries, attributed the high attrition rate in January to the extra work players are putting into conditioning over the offseason.

"If I know them well, the top players, they still will be in good shape when it comes to the Australian Open," Petkovic said.

Advancing to the men's quarterfinals were second-seeded Kei Nishikori, who opened with a 6-3, 6-4 win over Mikhail Kukushkin; third-seeded Marin Cilic, who beat Hyeon Chung 7-5, 7-6 (3); and No. 8 Dominic Thiem, a 6-3, 6-2 victor over Denis Kudla.

At the Hopman Cup mixed teams event in Perth, the Australia Green team of Nick Kyrgios and Daria Gavrilova remained unbeaten with a 2-1 win over Britain, which dropped to 1-1.

Andy Murray lost to Kyrgios 6-4, 7-6 (6) before Heather Watson came back to beat Gavrilova 6-7 (2), 6-2, 7-5. In the deciding mixed doubles, Kyrgios and Gavrilova prevailed 6-2, 6-7 (0), 11-9, with the British team saving three match points before Kyrgios clinched it with an ace.

Germany leveled its record at 1-1 with a 2-1 win over France, which lost for the second time.

Alexander Zverev gave Germany a 1-0 lead with a 6-2, 6-2 win over Kenny De Schepper, but Caroline Garcia beat Sabine Lisicki 6-2, 7-6 (5) to send the match to a mixed doubles decider, which the German pair won 6-4, 6-7 (6), 10-6.

In New Zealand, third-seeded Caroline Wozniacki had a 6-0, 6-2 win over Christina McHale and Sloane Stephens beat Carina Witthoeft 3-6, 6-1, 6-3.

Austrian qualifier Tamira Paszek beat two-time Grand Slam champion Svetlana Kuznetsova and British qualifier Naomi Broady reached the quarterfinals with a 4-6, 7-6 (4), 7-5 win over Jelena Ostapenko of Latvia.