'S-HERTOGENBOSCH, Netherlands - Kazakh teenager Elena Rybakina knocked off two-time finalist Kirsten Flipkens to continue a career-best campaign at the Libéma Open on Friday.

With a 6-4, 6-4 victory over the five-time quarterfinalist, the 19-year-old booked a spot in her first WTA semifinal, which will be opposite No.1 seed, World No.4 and local favorite Kiki Bertens.

"It was a tough match," Rybakina said. "Every match is tough for me. I'm happy because I served well today and I think this was the key. I played good."

Having already reached two tour-level quarterfinals in her young WTA career previously, Rybakina broke new ground for a result that she was tantilizing close to on the terre battue in the clay-court season.

She was a set away from her first semifinal place in a tour event at the Istanbul Cup in April, before Barbora Strycova rallied from a 0-6, 7-6(6), 6-0 win, but saw no such struggles against another wily veteran on Friday.

The hard-hitting qualifier, who finished off an upset of No.9 seed and Flipkens' compatriot Alison van Uytvanck on Thursday, was quick out of the gates to begin the match.

Read more: Rybakina upsets van Uytvanck to make Den Bosch quarters

Rybakina broke Flipkens in the third game and held on to her lead for the duration of the opening set, and later scored what proved to the decisive break in the fifth game of the second.

That came only after she triumphed through her toughest hold of the match, where she saved four break points in a mammoth 10-deuce game which would've seen the former Wimbledon semifinalist open up a 3-1 lead.

The World No.134 did not face a break point for the match overall outside of that game, and cruised through to her first-ever semifinal on serve from there, surrendering just three points in three games.

"I'm going to rest a little bit and like before, I will talk with my coach and we will watch some of her matches," Rybakina said of Bertens up next. 

"She's a top player, a great player, and I want to play with such players, so I will try my best."