Wozniacki ground out a 4-6, 6-3, 6-4 win to join a powerful last eight, where she will play defending champion Agnieszka Radwanska. Maria Sharapova, Samantha Stosur and World No 1 Victoria Azarenka are also through.
Elsewhere, Sharapova found improved form to reach the quarter-finals — but still needed a second-set tie-break to shake off Lucie Safarova 6-2, 7-6 (7/5).
In the quarter-finals today, Sharapova will play eighth seed and former US Open champion Samantha Stosur of Australia, who defeated Dominika Cibulkova of Slovakia 6-4, 7-5.
Belarusian top seed Azarenka outlasted Roberta Vinci of Italy 6-4, 6-2 to set up a meeting with Angelique Kerber, while last year’s winner Radwanska, the third seed, defeated qualifier Jamie Hampton of the United States 6-4, 6-3.