The defending champion ousted Alison Riske in straight sets in Thursday's quarterfinals.
WTA Staff

RNBERG, Germany - Defending champion and top seed Kiki Bertens hammered seven aces and lost serve just once in defeating American Alison Riske, 6-4, 6-3 to advance to the semifinals at the Nürnberger Versicherungscup.

Bertens has won all six sets in three matches played in her title defense, and sets up a meeting with Misaki Doi for a place in the final.

"I think I played really well today - Alison was also playing great," Bertens said later after the match. "[She] started the match really well, so I had to really step up my game, play more aggressive and serve well, and it worked out today."

Though the top seed fell behind an early break in the opener, she quickly rebounded to win the last four games for a one set lead. The World No.19 earned her first break of the American's serve to even the set at 4-4, and again broke the American's delivery to win the set.

Bertens faced no such issues in the second set, as she served at a nearly 90 percent clip, and won over 70 percent of the points played behind her first serve. A lone break in the eighth game gave the top seed a 5-3 lead, and she served the match out with aplomb to 15. 

Bertens will face the unseeded Doi for a spot in the the final, as the Japanese player was given her second retirement of the tournament by No.7 seed Yaroslava Shvedova earlier on Thursday.

"Misaki is playing some good tennis over the past few weeks," Bertens said. "It's going to be tough also, but I will enjoy it."