Serena reaches quarters in Dubai

Dubai, United Arab Emirates ( - World No. 1 superstar Serena Williams was a second-round winner Tuesday at the $2 million Dubai Tennis Championships.

Williams, playing her first tennis since losing to Ana Ivanovic in the fourth round at the Australian Open last month, was tested mightily in the first set before settling for a 7-6 (10-8), 6-0 victory over Russian Ekaterina Makarova on the hardcourts at Dubai Tennis Stadium.

The 32-year-old Williams is also recovering from a back problem that plagued her in her Aussie Open loss.

The reigning U.S. and French Open champion's quarterfinal opponent on Thursday will be fifth-seeded Jelena Jankovic or Czech Lucie Safarova.

No less than three former No. 1s saw opening-round action on Tuesday, and all three moved on. Jankovic handled Ukrainian qualifier Maryna Zanevska 6-4, 6-3, while Ivanovic upended sixth-seeded German and last week's Doha runner-up Angelique Kerber 3-6, 6-3, 7-6 (8-6), and eighth-seeded former U.S. Open runner-up and 2011 Dubai titlist Caroline Wozniacki overcame last year's Wimbledon runner-up Sabine Lisicki of Germany 2-6, 6-3, 6-3.

"I knew she was going to come out hot and just go for her shots, and I felt like I was just a step behind," Wozniacki said after besting the big-serving Lisicki.

Also in the first round, France's Alize Cornet was leading last week's Doha champion Simona Halep 6-1, 1-1 when the seventh-seeded Romanian retired on Day 2, citing an Achilles injury and fatigue.

"After one set I realized that it is dangerous to continue," Halep said.

In some other first-round play, German qualifier Annika Beck took out former U.S. Open champion Sam Stosur 1-6, 6-1, 6-4, Belgian Kirsten Flipkens topped Czech qualifier Karolina Pliskova 6-1, 7-5, and Italian qualifier Flavia Pennetta foiled Estonian slugger Kaia Kanepi 7-5, 6-4. Pennetta is rewarded with a second-round match against second-seeded former Wimbledon finalist and 2012 Dubai champ Agnieszka Radwanska.

The second round will conclude Wednesday, including matches for Radwanska, third-seeded reigning Dubai champ Petra Kvitova, fourth-seeded 2013 Dubai runner-up Sara Errani, Jankovic, Wozniacki, and Ivanovic, who will take on fellow former world No. 1 and two-time Dubai titlist Venus Williams.