DOHA, Qatar - Petra Kvitova appeared on course to grab the final spot in the Qatar Total Open final four before Julia Goerges was forced to retire trailing, 6-4, 2-1, due to a hip injury.

"I injured my hip a week ago here, on Saturday," Goerges explained after the match. "I played all my matches on pain killers, but now it's different spot in my hip. This morning, I woke up, and felt it; I'm not sure exactly what it is, but the tablets didn't help, especially when I have to bend deep down into the ball."

Kvitova and Goerges battled to three sets two weeks ago at the St. Petersburg Ladies Trophy, but Kvitova was in control from the first ball on Friday, striking 13 winners to just seven unforced errors and converted both break points she engineered to remain in the lead when Goerges could no longer continue.

"I finished pretty late yesterday, and it took me a while to get to sleep," Kvitova said after the match." Now my body is a little bit tired. I was pretty lucky to get another night match, so I could get my sleep and everything I needed. It was a great start from me. From the beginning, I was dictating the game, and that was putting pressure on her. She serves well, but I was stepping in on second serves and I think that made her hit some double faults. I served pretty well too.

"She said she had something with her hip and when I made her run, she felt it, and we spoke about that at the net."

The win nontheless marks the two-time Wimbledon champion's 11th in a row, with a potential return to the Top 10 on the horizon should she capture the title in Doha.

"I'm trying! It's amazing," she said during her on-court interview. "It's my sixth appearance in Doha and my first semifinal. I'm very happy with that. I'm trying to continue my streak, but it's not easy, especially since Julia has been playing great. Unfortunately, she had to retire, but I hope she's able to come back soon."

Standing between her and a spot in the final is top seed and World No.1 Caroline Wozniacki, who had a much longer day out there on Centre Court as she needed two hours and 20 minutes to defeat two-time Grand Slam champion Angelique Kerber in three sets.

"We're deeper in the tournament now. When I came here, it was a pretty quick turnaround and different conditions. I felt empty against Aga, and that's especially tough, and I knew how difficult that match would be going in. After that, things got much better, and I felt much calmer yesterday, focusing on the game. Today I felt even better."

Kvitova and Wozniacki have played 12 times, with the Czech powerhouse winning their last three meetings - most recently at last year's China Open.

"It'll be a different story; we're both in different form now. She's won a Grand Slam, so she must have so much more confidence than she had during all those years when she was fighting for it. She became No.1 again, and she must be playing well or else she wouldn't have beat Kerber today.

"Clearly she's improving, so I'll need to be ready for that. I'm sure she had a great off-season, so I'll have to focus on an aggressive gameplan."