KEY BISCAYNE, Fla. -- Caroline Wozniacki advanced to the quarterfinals of the Miami Open after Garbine Muguruza retired with illness on Monday.
No. 6 seed Wozniacki was up a set 7-6 when the Spaniard retired due to heat-related illness after a visit from doctors.
The Dane faces the winner of Dominika Cibulkova or Lucie Safarova.
No. 2 seed Karolina Pliskova also advanced to the round of eight wth a straight sets 6-1, 6-4 win over compatriot Barbora Strycova.
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