BIRMINGHAM, England (AP) -- Former world No. 1 Ana Ivanovic, who admits to a dislike of competing on grass, moved within one win of her first final on the surface with her third confident win in a row at the Aegon Classic on Friday.

The top-seeded Serbian beat the sixth-seeded Czech, Klara Koukalova, 6-1, 6-4 to reach the semifinals of the Wimbledon warmup event.

Ivanovic has described playing on grass as ''like being stuck to the ground all of a sudden,'' but there was little wrong with her movement nor any evident lack of self-belief as she forcefully completed her win in 72 minutes.

There was a 20-minute phase in the second set when Koukalova, who has a grass-court title to her name, seemed capable of regaining parity and held service up until 4-3.

But Ivanovic boldly attacked off the ground to break serve in the psychologically crucial moments of the ninth game, and closed out the match without fuss.

''It's a tough transition, not only in the body and the movement, but also in the mindset,'' she said of her improved grass-court showing. She even agreed she was now able to believe she could win the tournament.

''I have more confidence. It's about rhythm and getting ready for the next match. Now I have the flow,'' she said.

Ivanovic will meet surprise semifinalist Zhang Shuai, the ninth-seeded Chinese player, who patiently took advantage of an error-prone, self-critical Sloane Stephens, the third-seeded American, to win 6-3, 6-1.

There will not be a fairytale finalist in the bottom half. Kimiko Date-Krumm, the 43-year-old Japanese who sensationally ousted defending champion Daniela Hantuchova on Thursday, was unable to emerge fresh for a fourth consecutive day, lasting only three-quarters of an hour in a 6-1, 6-0 loss to Casey Dellacqua of Australia.