Angelique Kerber cruised past Caroline Wozniacki. Victoria Azarenka also made the quarters.
WTA Staff

STUTTGART, Germany - If her meteoric rise didn't seem headed towards the Top 10 already, maybe now it will. Angelique Kerber crushed World No.6 Caroline Wozniacki in the second round of the Porsche Tennis Grand Prix, 61 62, and has now won five of her last seven matches against the Top 10.

Watch Stuttgart & Fès this week on WTA Live powered by TennisTV!

Having come out of the Australian season with an 0-12 record against the elite, Kerber has gone 5-2 against them since February, two of those wins coming against Wozniacki, first in the final of Copenhagen two weeks ago and now in Stuttgart. This time she went on a mid-match tear, winning nine games in a row from 1-all in the first set to build a 61 40 lead, closing it out four games later.

"It was a very perfect match," Kerber said. "Caroline is a great player, a Top 10 player and No.1 in January, so to beat her twice in the last two weeks gives me a lot of confidence. It doesn't matter if I'm playing on hard or clay, I feel very good on both surfaces. And I feel very good here. The crowd is unbelievable."

The news wasn't as good for the other German in action in the evening session, as Andrea Petkovic's second set fight-back against World No.1 Victoria Azarenka was stopped due to a right ankle injury. Azarenka had built a 62 42 lead but Petkovic rallied to make it 4-all and even had game point to win three in a row, but then the injury struck and Azarenka advanced, 62 44 retired.

"My ankle swelled up as soon as I twisted it," Petkovic said. "I don't know how bad it is at the moment, but we are checking the ligaments for any damage. Right now I'm just icing it and then tomorrow I will have an MRI and a CT."

Petkovic was playing her first WTA tournament after three and a half months out with a back injury. "It was really nice to play in front of this crowd," the German commented. "I just kept fighting and trying to stay in the game and they definitely helped me with that. It was a really nice atmosphere out there tonight and I think it was really nice to start a little comeback here in Stuttgart.

"Just as I was beginning to find my rhythm and my strength again, I rolled my ankle. It's definitely unlucky, but I'll be back again."

"I feel really bad for Andrea. I hope she recovers and we see her back on the court soon," Azarenka said. "This was my first match on clay so I wasn't looking for perfection out there. I just tried to find my rhythm and my game on clay. We had some good rallies and played some good points, so I'm happy."

Azarenka got her 27th win of the season, matching Agnieszka Radwanska.

All four quarterfinals will take to the clay of the Porsche Arena on Friday, with top seed Azarenka taking on wildcard Mona Barthel, No.2 seed Maria Sharapova playing No.5 seed Sam Stosur, No.3 seed Petra Kvitova playing Angelique Kerber and No.4 seed Radwanska facing No.8 seed Li Na.

Azarenka has beaten Barthel all three times they have played before, all of those coming this year in fact, although their last encounter was a thriller.

"Mona has shown some great results this year and I've played her a lot of times," Azarenka said. "She might have a little bit of an advantage with the home crowd, but I'll go out there and try my best. It will be a new match."