Stosur was down 4-2 in the second set before hitting back to win 4-6, 7-6 (7-4), 6-4 in just under three hours at Devonshire Park.
The Queenslander will now meet Marion Bartoli for a place in Saturday's final, after the Frenchwoman's opponent, Victoria Azarenka, was forced to retire.
Stosur says she is certain she made the right decision in missing Australia's Fed Cup tie loss to Ukraine in April.
She chose to stay in Europe to prepare for the claycourt season rather than return to Melbourne for a World Group play-off tie eventually won by the visitors.
Despite the shock loss, Stosur says it was the correct decision in what was a difficult situation for both her and the team.
"I definitely wanted to be there if it was possible, but it was a decision I made for my schedule and to stay over in Europe," she said.
"I don't think it was an ideal situation for anyone to have to go back. I made that choice and I still thought the girls could have been able to win."
Meanwhile, Daniela Hantuchova ended the Williams sisters' run at Eastbourne, as she finally triumphed after 10 losses in her career series with Venus.
Hantuchova, who had won just two sets previously against the American holder of five Wimbledon titles, secured a gritty 6-2, 5-7, 6-2 quarter-final victory to send Venus out a day after her sister Serena lost to top seed Vera Zvonareva.
Hantuchova, ranked 25th, laboured for two hours and 23 minutes after a delayed start due to rain in the area. The Slovak, who played last week's Birmingham final, won her 27th match of the season and heads into a semi-final against fifth seed Petra Kvitova, who beat Agnieszka Radwanska 1-6, 6-2, 7-6 (7-2).
In other results at Eastbourne, the men finally completed three left-over second-round matches topped by rain on Wednesday.
Janko Tipsarevic, the number three and last seed remaining, beat Mikhail Kukushkin 6-3, 7-6 (7-2), Belgian Olivier Rochus stopped Argentine Carlos Berlocq 3-6, 7-6 (7-5), 7-6 (7-3) and Japan's Kei Nishikori beat German veteran Rainer Schuettler 6-4, 4-6, 6-2.
- ABC/AFPTags: sport, tennis, australia, united-kingdom, england First posted June 17, 2011 06:12:00