Few were as stunned by Kiki Bertens’ Cinderella run to the semifinals of Roland Garros than Bertens herself. The Dutch star celebrated her almost improbable quarterfinal win over No.8 seed Timea Bacsinszky with a shrug.

“I was like, Can you believe it? Because I cannot. And also my parents were like, No, this is not happening. But, yeah, it is.”

Her run of 12 straight wins – not including a doubles victory over the Williams sisters – began as a qualifier at the NÜRNBERGER VERSICHERUNGSCUP, which she won before reaching the second week of a Grand Slam for just the second time in her career, all but guaranteeing her spot on the Dutch Olympic team at the upcoming Summer Games in Rio de Janeiro.

“I think in the preseason I did a lot of work. Like the first three weeks was only physical practices, like two, sometimes three times a day.

“It was a hell really, but I’m really glad we did it. Like with my whole team we were working really hard every day.”

For all of those reasons, Bertens is your Breakthrough Player of the Month!

Final Results for May’s WTA Breakthrough Performance Of The Month

1. Kiki Bertens (69%)
2. Shelby Rogers (16%)
3. Yulia Putintseva (12%)
4. Louisa Chirico (3%)

2016 Breakthrough Performance Of The Month Winners

January: Zhang Shuai
February: Jelena Ostapenko
March: Nicole Gibbs
April: Cagla Buyukakcay