PARIS, France – Kiki Bertens continued her French Open fairytale on Thursday afternoon with a straight set victory over No.8 seed Timea Bacsinszky.

Prior to this fortnight, Bertens had only ever been beyond the second round of a major once before – reaching the fourth round here in 2014 – but after defeating Bacsinszky, 7-5, 6-2, she will now face reigning champion Serena Williams for a place in the final.

An opening set littered with breaks and momentum shifts hinged on the 11th game when Bertens bucked the trend by holding serve. A sequence of errors from Bacsinszky brought three set points, Bertens wrapping it up courtesy of a thumping forehand.

By contrast, the second set was all Bertens, her confidence soaring after prevailing in the 70-minute opening stanza. Understandably given her recent exploits – this was her 20th match in singles and doubles in the past 20 days – the Dutchwoman began to run out of steam as the finishing line approached.

Bacsinszky, though, proved to be equally exhausted, dragging a forehand wide to bring up match point. Moments later it was over – Bertens tumbling to the clay, scarcely able to believe her accomplishment.

Afterwards, Bertens was quick to highlight the importance of the see-saw first set: “I think it was really difficult today. The circumstances were really tough. The court is really slow. The balls are heavy. It’s really tough to play aggressive, and especially with Timea. She is like changing a lot, like with some slower balls and some higher ones, so it was pretty tough for me.

“But I think afterwards I was 4-2 down, and then I was just like, Okay, we are just going to be calm and try to fight for each point. I did it and I won the first set. Yeah, it was just keep on fighting for every ball.”

The last Dutchwoman to make it this far at one of the four majors was Betty Stove, who lost in the semifinals of the 1977 US Open, while the last in Paris was Marijke Schaar, six years earlier.

It has been a remarkable clay court season for Bertens, who kicked it off by nearly leading the Netherlands to the Fed Cup title. This was followed by a semifinal in Rabat and then a title in her last tournament before Roland Garros, in Nürnberg.

The turning point came in Rabat, a particularly painful loss to Marina Erakovic leading to a frank post-mortem in the Bertens camp. “I remember like one thing I remember is like my semifinal in Rabat. I had match point there I was losing the match and I wasn’t just – in my head I was so stressed and all the time and we were like talking with my coach after that match for so long.

“I think after that match I just was so calm in my head and just trying to go out there every day and just give everything and then, yeah, just do my own thing. I think that’s the most important thing.”

Having ended 2015 at No.101, the new rankings will see Bertens break into the Top 30 for the first time in her career. It is the reward for an arduous training regime that allowed Bertens outplay and outlast Angelique Kerber, Daria Kasatkina, Madison Keys and now Bacsinszky.

“I think like in the pre-season 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 like working every day like really hard. Physically I feel good the whole year. I played a lot of matches, so I feel good.”