American Madison Keys, the No 4 seed, moved into the semi-finals of the Eastbourne Open after Karolina Muchova withdrew before the match at Devonshire Park Lawn Club.
Keys, ranked No 12, will play Canadian Leylah Fernandez next.
Ahead of her victory, the American won against Ukrainian qualifier Anhelina Kalinina (7-6 (5), 6-1).
Muchova, ranked No 35, benefited from the abandonment of Russian qualifier Elina Avanesyan (3-1) and beat Pole qualifier Magda Linette (6-4, 6-1) in the previous rounds of the Eastbourne tournament.
Eastbourne WTA 500, other last-eight results (Devonshire Park Lawn Club, grass, USD 922.573, most recent results first):
