CINCINNATI, OH, USA - Greece's Maria Sakkari recorded her fourth Top 10 victory of the season on Tuesday night at the Western & Southern Open, as she downed No.6 seed Petra Kvitova in the second round, 6-4, 2-6, 6-3.

After winning the first set, Sakkari found herself ultimately down a break in the decider against the two-time Wimbledon champion, but won five of the last six games to seal a second win in three meetings against the Czech this year.

"She's an unbelievable player. There's no doubt...she plays extremely fast and puts you in a position where you feel uncomfortable with your tennis," Sakkari said on-court after the match.

"I just fought hard and made a lot of balls. Fighting hard, that's my spirit. I feel really good and very confident to be playing against these players. A few years ago, I was just watching them on TV back home.

"I never thought I would be here, playing against them and winning against them. It's a dream coming true for me."

Related: Kvitova finding her way after arm injury: 'I feel like I forgot how to play the forehand'

Playing just her second tournament since May and her first since Wimbledon after being plagued by a left arm injury, Kvitova could not overcome both her own rust, and the varied play by the Greek No.1 around the court. 

Though both players were broken four times in the match, Kvitova racked up nine double faults and 53 unforced errors over two hours and eight minutes, accumulating just 25 winners. 

"It was a very close match, and a very close three sets. I think she played very good in the second set, especially," Sakkari added after the match.

"She came up with some great tennis as always. I kept the rallies long and kept the ball on court, and just running and making more balls. I think that was one of the keys to getting the win today.

"I did some adjustments compared to how I played her in Miami [a 6-4, 6-1 win for Kvitova], because there, she was dominating the whole match. I had to do something to take her out of her comfort zone, so that's what I tried to do in Rome and here.

"In Rome, I had more time because it's clay and it's a slower surface, so I tried to adapt the same tactics as I did [on clay], but on that court here."

Three of those double faults came in the penultimate game for the break that helped Sakkari seal the match. The Czech threw in two consecutive doubles to give Sakkari an opening in the eighth game, and handed over a third on the second break point of the game.

Up next, Sakkari will face the winner of the match between No.9 seed Aryna Sabalenka and China's Zheng Saisai, which is a rematch of the Mubadala Silicon Valley Classic final from earlier this summer.

Sakkari lost to Zheng in the semifinals in San Jose in straight sets, 

"Aryna is a very powerful and aggressive player and you need to play different than if I play Saisai," the Greek said.

"If I play Saisai, will have to do everything different that I did in San Jose, because the result was not great. She plays different, so I will have to adapt."