CINCINNATI, OH, USA -- 2013 Cincinnati champion Victoria Azarenka of Belarus moved into the second round of the 2019 edition of the Western & Southern Open, after No.12 seed Belinda Bencic retired due to a left foot injury while the Swiss trailed 6-4, 1-0.

"I know all about injuries and how frustrating it is, and especially right before the last major of the year," Azarenka said, during her post-match press conference. "I hope [Bencic] recovers quick."

Former World No.1 Azarenka had defeated Bencic in their only prior meeting, at Wimbledon in 2015, and extended her head-to-head lead to 2-0 after former Top 10 player Bencic ended the match after 50 minutes of play.

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Two-time Grand Slam champion Azarenka had eight winners and a matching number of unforced errors during the clash, while Bencic's 15 winners were overcome by her 19 unforced errors. Azarenka converted four of the five break points she held in the match.

"I think that she started, you know, really well," Azarenka admitted. "In the beginning she was very aggressive, which I didn't necessarily expect that from the get-go. I feel that she's the type of player that is more about redirecting the ball, using your pace and mixing it up. So that was a little surprising."

"But I felt that I fought back well in that first set and took my opportunities, put a lot of pressure on her," Azarenka continued. "Served smarter than the beginning. I moved quite well. I felt there was a lot of good rallies we had today."

Bencic grasped the early lead at 2-0, but that simply started a run of four straight service breaks which ended with the players back on serve, as they moved to a 3-3 tie. But Azarenka then went up a break for the first time at 4-3, after Bencic fired back-to-back double faults to drop serve for the third time in the set.

Azarenka retained that break and served for the set at 5-4, where a strong serve forced a short return by Bencic and gave the Belarusian double set point. Aggressive play by Bencic pulled her to deuce, but effective hitting from the forehand side gave Azarenka a third set point. The third time was the charm for the former World No.1, as a netted return by Bencic gave her the one-set lead.

The Belarusian fired a fierce forehand to garner a break of service in the opening game of the second set, after which point Bencic requested a visit from the trainer. After a brief consultation, Bencic decided she was unable to continue, and walked over to share a handshake and a hug with Azarenka.

Azarenka will now face either Donna Vekic of Croatia in the second round. Vekic defeated Katerina Siniakova of the Czech Republic in straight sets on Tuesday. Vekic won their only prior meeting, just two weeks ago in San Jose.

"It's gonna be a fight, you know," said Azarenka. "[Vekic is] a great player. I need to be able to play strong in the tough moments and in tough matches. Every match here is going to be tough."