Former world No. 1 and reigning Australian Open champion Victoria Azarenka was a second-round winner Tuesday, while American Sloane Stephens rallied to beat a returning Maria Sharapova at the $2.369 million Western & Southern Open tennis event.

After enjoying an opening-round bye, the second-seeded Azarenka and 2012 U.S. Open runner-up handled American qualifier Vania King 6-1, 7-6 (8-6) on the hardcourts at the Lindner Family Tennis Center.

Stephens claimed just two games in the opening set before advancing to the third round with a 2-6, 7-6 (7-5), 6-3 victory over the third-seeded Russian. It was Stephens' second career top 10 win.

Sharapova, who titled here in 2011 and was the runner-up in 2010, played her first match since Wimbledon. A left hip injury resulted in her withdrawing from tournaments in Stanford and Toronto.

Meanwhile, 10th-seeded Dane Caroline Wozniacki posted an easy 6-1, 6-1 first- round win over China's Peng Shuai and 14th-seeded Serbian Jelena Jankovic fought past Wimbledon finalist Sabine Lisicki, 7-6 (7-5), 5-7, 6-2.

Jankovic captured this Cincy event in 2009 and was the 2011 runner-up to Sharapova.

A pair of seeded players were dismissed in round one. Russian Elena Vesnina upended 13th-seeded Belgian Kirsten Flipkens, 3-6, 6-1, 6-3, and France's Alize Cornet knocked off 15th-seeded former No. 1 Ana Ivanovic 2-6, 7-6 (10-8), 6-4.

Americans notching opening-round wins were Jamie Hampton and Varvara Lepchenko. Hampton snuck past Russian Anastasia Pavlyuchenkova 7-5, 4-6, 6-3, while Lepchenko held off Italian veteran Flavia Pennetta 6-2, 2-6, 6-2.

Also posting first-round wins were Germans Mona Barthel and qualifier Andrea Petkovic, Russian Ekaterina Makarova, Slovak Magdalena Rybarikova, lucky loser Monica Niculescu, and Slovenian qualifier Polona Hercog, who upset recent Stanford titlist Dominika Cibulkova, 6-2, 6-4.

Niculescu replaced fellow Romanian Sorana Cirstea, who withdrew from the tournament two days after losing to Serena Williams in the Rogers Cup final.

This week's winner will earn $426,000. The tournament is part of the U.S. Open Series, or the North American hardcourt events that lead up to the U.S. Open, which will commence August 26.