AUCKLAND, New Zealand -- World No. 4 Agnieszka Radwanska was taken to tiebreaks in both sets by unheralded American Jamie Hampton before edging her way into the final of the ASB Tennis Classic.
Top-seeded Radwanska had dropped only 10 games on her way to Friday's semifinal, sweeping her first three matches in straight sets, but was fully taxed by the 71st-ranked Hampton before winning 7-6 (4), 7-6 (3).
Poland's Radwanska will now face third-seeded former champion Yanina Wickmayer in Saturday's final. Wickmayer reached her third singles final in Auckland when she beat eighth-seeded German Mona Barthel 6-4, 1-6, 7-6 (3).
Radwanska, ranked 14 places above her nearest rival in Auckland, had looked a cut above the field as she eased into the semifinals with wins over fomer champion Greta Arn, Simona Halep and Elena Vesnina.
The slightly-built Pole plays mostly from behind the baseline, keeping the ball in play through long rallies and often catching out opponents with her ungainly, crouching forehand and off-balance backhand.
But she found it difficult against Hampton, who had beaten defending champion Zheng Jie, local hope Marina Erakovic and Kiki Bertens on her way to the semifinals.
After the first set had gone with serve to 5-5, Hampton became the first player in Auckland to break Radwanska's serve and led 5-6. She held a set point on serve but double faulted, then dropped serve to cause a tiebreak.
Neither player served well in the tiebreak, put off by a swirling wind, and there were six mini breaks before Radwanska clinched the game and set in 61 minutes.
Radwanska then dashed to a 4-0 lead in the second set as Hampton seemed deterred by her failure to convert her set-point chance. But, just as it seemed Radwanska would stroll to victory, the American won the next four games to tie the set and set up a second tiebreak.
Again, Radwanska managed to win a handful of vital points to clinch the set and match.
"Actually, it was very tough and I was just happy to be two points better in each set," Radwanska set.
Wickmayer was also forced to work hard for the three-set win over Barthel. Barthel had seven aces to one but also eight double faults.
Two of those double faults came in the tiebreak in the final set, putting Barthel behind 4-1 and she couldn't recover.
"It was really tough today. It was up and down the whole match," Wickmayer said.
"I started well but she came out really agressive in the second set, particularly against my serve. I went to the bathroom and thought it all through and focused on playing my best tennis. I was lucky it went my way in the third set."