STUTTGART, Germany – WTA World No.1 Naomi Osaka has been forced to withdraw from the Porsche Tennis Grand Prix due to an abdominal injury.

The two-time Grand Slam champion had been slated to play No.8 seed Anett Kontaveit in the semifinals of the tournament, but the Estonian will now receive a walkover into the fifth WTA Tour final of her career.

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Osaka’s withdrawal comes hours after she pulled off a miraculous comeback in the last eight, where she defeated Donna Vekic in unlikely fashion. In the deciding set, the Japanese found herself trailing 5-1, and yet she found the resources to turn the situation around and take the match on a tiebreak after two hours and 18 minutes.

It was an even more remarkable victory given that she felt the beginnings of her injury surface.

“I felt it yesterday at the start of the match,” she confessed. “She was asking me in the third set why my serve dropped and it was actually for that reason. 

“I wanted to wait to see if I could play. I woke up today and I had to roll out of bed, then I decided I wasn’t able to play.”

Despite the blow, she remains confident there is no long-term damage, having suffered a similar problem regularly throughout her career.

“It’s something I’ve had before. It’s an ab strain. Thankfully because I’ve had it so many times, I’m able to tell what it is and I’m able to know what to do to make it better. 

“I have it at least once every year. It takes a few days to not feel it, then I just have to strengthen. It really depends on how bad I tore it. I don’t think it’s that severe, but it’s still a bit concerning.

“Even though it’s bad I got injured here, I’m happy it was the beginning and not Rome, when it’s really close to the French Open.”

The 21-year-old has admitted that she has had her struggles on the dirt in the past, so it will be a particular disappointment that, having worked so hard on the surface, she has been denied the opportunity to fight for her place in a WTA clay court final for the first time.

Speaking after her victory over Vekic, she commented: “I spent a really long time after Miami just training on clay, trying to get comfortable with it. And I’m really happy that that paid off. I think every day I’m improving which is really good to see. So, hopefully by the time French comes I’m a decent clay court player.”

Wins over Hsieh Su-wei and Vekic, the WTA World Nos. 25 and 24 respectively, are the best that Osaka has achieved in her career on the surface, which bodes well for Paris, where she has never reached the second week.