Petra Kvitova will face Caroline Wozniacki in the semi-finals of the Qatar Open after Julia Goerges withdrew from their last-eight match on Friday.
Kvitova, seeded 16th for the WTA Premier 5 event in Doha, broke her German opponent, who is 11 places above her in the rankings at world number 10, in the third game before taking the opening set 6-4.
The Czech led 2-1 in the second when ninth seed Goerges was forced to bring a premature conclusion to the contest.
Wozniacki, the Australian Open champion, had earlier seen off Angelique Kerber in a thrilling three-set contest that secured the Dane's status as world number one, Simona Halep having also been forced to pull out of the tournament despite reaching the semi-finals with a victory over CiCi Bellis.
