BEIJING, China -- Two-time Grand Slam champion Petra Kvitova extended her run at the China Open on Tuesday, defeating American qualifier Varvara Lepchenko in the second round by the score of 6-4, 6-4.

In a battle of left-handers, the Czech No.12 seed was rarely tested in the 78-minute match, and improved her flawless head-to-head record against the American to eight wins and no losses.

Kvitova, the 2014 China Open runner-up (l. Sharapova) and a quarterfinalist last year, had a good serving day, with four aces and winning 88% of points on her first serve. Lepchenko was able to break Kvitova both times she had break points, but Kvitova's sturdy hitting gave her four breaks of her own.

The first of Kvitova's breaks came at 1-1, when the Czech hit a powerful forehand barely in the court, forcing a Lepchenko error into the net. But the American would level the match at 3-3, after Kvitova was broken in a game which contained two double faults.

But Kvitova quickly reclaimed her single-break advantage in the very next game, as Lepchenko ceded her service once more with multiple misfires into the net off of her groundstrokes. That lead was all that Kvitova would need, and at 5-4, she served out the set at love.

Kvitova then jumped out to a lead in the second set, easily breaking Lepchenko in the opening game. But Lepchenko was unbowed, directly breaking back in a difficult game, and then holding for 2-1 to assert herself in the match.

But more solid serving by Kvitova kept her on the offensive, and at 3-3, the Czech finally saw another chance to reclaim a decisive advantage. Thunderous shotmaking, including off the return, brought Kvitova to break point, and she broke for 4-3 when Lepchenko hit an unforced error off the backhand side.

The two-time Wimbledon winner held at love for 5-3, and Lepchenko's next service game turned from routine into a struggle, as Kvitova hoped to break serve for the victory. But Lepchenko held in a tense game, and made Kvitova mull over a chance to serve for the match at the changeover.

If Kvitova was bothered, though, it did not show. She opened the game with an incredible backhand winner down the line, and after two of Lepchenko's groundstrokes went long, the Czech found herself at triple match point. Kvitova only needed one, and claimed victory after Lepchenko sent a service return into the net.

Kvitova's win sets up a tantalizing third-round tussle with No.5 seed Caroline Wozniacki of Denmark. Kvitova holds a slight 6-5 lead in her head-to-head record against the Dane, and another intriguing encounter in their eight-year rivalry is sure to follow in Beijing.

"Caroline is playing well," Kvitova said. "It will be a very good match. I showed myself I can compete against the top players at the US Open, so I am looking forward to a big match again.

"Every time you play against a better opponent you are playing better as well because you know if you play so-so it won't go well on the court. I am trying always to be the best for myself."