STUTTGART, Germany - No.3 seed Petra Kvitova closed out a dramatic penultimate game to defeat rising Belgian Greet Minnen, 6-1, 6-4, and reach the last eight at the Porsche Tennis Grand Prix.

"I think I started pretty well," Kvitova told the press, after her victory. "I think that I was ready from the first point. I didn’t know the opponent which is always tricky, so I was really focusing."

"You know, playing on the clay the first time is always kind of difficult," the World No.3 continued. "I like playing indoor, but you know it’s kind of different playing here compared to other clay courts. I think in the end I served okay. A few of the games weren’t really perfect, but for the first match on clay it was fine."

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Playing her first match of the clay court season, Kvitova enjoyed a fast start but was made to fight for the finish line as Minnen saved five break points at 4-4 in the second set, emerging victorious after one hour and 13 minutes on court.

Minnen started the year with a first WTA quarterfinal at the Hobart International, and was fresh off one of the biggest wins of her career - knocking out 2014 Australian Open finalist and former World No.4 Dominika Cibulkova on Tuesday - but found Kvitova hard to solve early on as the Czech broke serve three times en route to a 5-1 lead.

The former World No.2 also shined on the Australian summer hardcourts, reaching her first major final since 2014 at the Australian Open - narrowly falling to Naomi Osaka in a thrilling final - and followed that up with another runner-up finish at the Dubai Duty Free Tennis Championships.

Against Minnen, she took the first set on her fourth opportunity and found things much tougher in the second set as the pair exchanged early breaks but remained on serve for most of the remaining contest.

The turning point came in the infamous tenth game, as Kvitova took a 0-40 lead and a chance to serve for the match. Minnen was unmoved, saving all three and holding multiple game points of her own to edge closer to a deciding set.

Kvitova ultimately reclaimed her rhythm and rode it to victory, holding serve to love.

"I had to fight at 4-4, that game was very, very important," Kvitova admitted. "I think [Minnen] just didn’t miss that much as she did in the first set."

"[Minnen] is playing a pretty flat backhand, great crosscourt, but the forehand definitely she can do a lot of spin, and she is a good mover as well," Kvitova stated. "She has a good serve, especially the first one, when it’s in, it's pretty fast and it’s really tough. And she has a kick -- which, probably not many players have that good kick as she has."

In all, Kvitova struck 25 winners to 29 unforced errors, converted five of 14 break point opportunities and struck four aces throughout the match.

Standing between Kvitova and a spot in the semifinals is either No.7 seed Anastasija Sevastova or 2017 champion Laura Siegemund, who also reached the finals in Stuttgart the year prior.