Fourth seed Wozniack followed first and second seeds Dominika Cibulkova and Yanina Wickmayer out of the tournament after she injured her shoulder during the warm-up before her second round encounter with Melanie Oudin.
The Canadian number one and local favourite was forced to pull out, handing American Oudin a walkover. She now plays Kristina Mladenovic of France for a place in the semi-finals.
Seventh seed Martic of Croatia fell to Anna Tatishvili, the Georgian player winning 6-2 6-3 to set up a quarter-final clash with Kirsten Flipkens, who ousted Cibulkova in the first round before seeing off Mirjana Lucic of Croatia 6-7(2) 6-2 6-4.
Number eight seed Lucie Hradecka, however, managed to avoid a slip-up against Canada's Eugenie Bouchard, the Czech winning 7-6(2) 2-6 7-6(4) to book a quarter-final date with America's Lauren Davis, conqueror of Wickmayer in the second round.
Defending champion Barbora Zahlavova Strycova plays Mona Barthel - the highest remaining seed at three - in the last quarter-final match-up.