Eighth seed Belinda Bencic and 15th seed Victoria Azarenka of Belarus became the latest seeds to crash out of the Dubai Duty Free Tennis Championship.

An ankle injury severely restrained the movement of the World No. 14, who lost to Madison Keys of the United States 6-2, 6-1 on Wednesday. Bencic, the Abu Dhabi Open winner, was humbled by Czech Karolina Muchova, who won 6-1, 6-4.

Keys advanced to the quarterfinals, where the World No. 23 will meet the winner of of the match between ninth-seeded Kazakh Elena Rybakina and fifth-seeded American Coco Gauff.

In other matches, third seed Jessica Pegula of the United States and Karolina Pliskova of the Czech Republic entered the last eight. Pegula despatched Romania’s Ana Bogdan 6-4, 6-3, while Pliskova overcame the challenge of Ukraine’s Anhelina Kalinina 7-5, 6-7 (6), 6-2.

Pegula will clash with Muchova, and Pliskova, the World No. 18, play top seed Iga Swiatek of Poland. Swiatek lived up to the billing with another demolition act. She trounced Liudmila Samsonova of Russia 6-1, 6-0 .