WUHAN, China - Unseeded Anastasia Pavlyuchenkova came from a set down to defeat two-time champion Petra Kvitova and reach the quarterfinals of the Dongfeng Motor Wuhan Open on Wednesday, 3-6, 6-3, 6-3. 

The World No.39 needed over two hours to score her best victory in terms of ranking since she defeated then-World No.3 Garbiñe Muguruza at the Porsche Tennis Grand Prix in April.

"It's my first Top 5 win in a while, so that means a lot and it's very special. Petra is a super tough opponent, and I knew that," Pavlyuchenkova said after the match.

"We've had many matches before [that were] always tough and I finally could get a win, so I'm really happy with that. I'm happy with the victory today, and let's see what's going to happen tomorrow."

The win ensures that the event will have a new champion in its fifth edition, with defending champion Caroline Garcia being eliminated in the second round, and two-time winner Kvitova going out in the third round. 

Though the Russian was the first to break serve in the match, building a 0-40 lead en route to winning Kvitova's third service game on her second chance to move ahead 3-2, that proved to be the last game she'd win in the opener.

The two-time champion in Wuhan powered through the next four games in a row, twice breaking the World No.39 to flip the set around to 5-3, and sealed the set in a titanic ninth game where she saved five break points.

Despite serving at just 42 percent, the two-time Wimbledon champion won over 70 percent of the points played on her first serve in the first set, and played well in the clutch to save six of seven break point opportunities she faced.

Nonetheless, Pavlyuchenkova rounded into form as the match wore on, with an early break in the second set helping her cause to take the match the distance.

The Russian led 0-40 in Kvitova's first serve game of the set, again breaking to 15, to take a lead she would never relinquish. Kvitova saved a break point in each of her next three service games, but clutch play on serve meant the Russian would not rue her missed chances.

The 27-year-old dropped just seven points on serve in the second set,  never facing break point, and hit nearly the same amount of winners to her Czech for (9 to 10) with less than half the unforced errors (6 to 14).

In the final set, the players traded early breaks, with the Russian earning the first advantage for the third straight set and Kvitova hitting back to level the action at 2-2.

However, after falling behind for the first time int he set, Pavlyuchenkova responded in a big way, and claimed the last four games en route to defeating Kvitova for the first time in six years.

Controlled aggression won out for Pavlyuchenkova over the course of two hours and 13 minutes, as she struck 21 winners to 19 unforced errors overall. 

The Russian created a staggering 21 break point opportunities over the course of the match, converting five, as Kvitova managed 28 winners to 37 unforced errors overall.

The Strasbourg champion will take on 2017 runner-up and No.16 seed Ashleigh Barty with a spot in the semifinals on the line.