American qualifier Jamie Hampton upset former world number one Caroline Wozniacki 6-7 (8/10) 7-5, 6-3 at the ATP-WTA Eastbourne International on Friday to reach the first final of her career.
The 23-year-old Hampton, ranked 41st, will move into position as national number three behind Serena Williams and Sloane Stephens after the best week of her career.
Hampton was the first US woman since Jennifer Capriati a decade ago to play the semis at Devonshire park and is the first qualifier on the WTA to reach a final this season.
She upset fifth seed Wozniacki while playing in only her third career grass event and will compete at Wimbledon next week for only the second time after reaching the second round a year ago.
Wozniacki was denied a chance at her second career grass court title after winning Eastbourne in 2009.
The pair had never played on the WTA, but that meant little to the determined Hampton, who kept up her game despite losing the opening set in a tiebreaker against her more experienced opponent.
Hampton levelled in a tight second set and sprang the upset of Wozniacki as she went up a break in the third and kept her winning margin to secure victory.
Hampton will face off in Saturday's final against the winner from Russian Elena Vesnina and Yanina Wickmayer of Belgium.