In the second round, Verdasco thumped unseeded Jan Hajek of the Czech Republic, 6-2, 6-2.
Elsewhere, No. 2 seed Filippo Volandri of Italy beat unseeded Sergio Roitman of Argentina, 6-7 (6-8), 6-1, 6-4; third-seeded Gilles Simon of France beat unseeded Mariano Zabaleta of Argentina, 7-5, 6-3; No. 4 Nicolas Almagro of Spain topped Frantisek Cermak of the Czech Republic, 6-1, 6-2; and eighth-seeded Ruben Ramirez-Hidalgo of Spain beat Gianluca Naso of Italy, 6-2, 6-2.
Other winners were Nicholas Lapentti of Ecuador, Alberto Motanes of Spain, and Martin Vassallo Arguello of Italy.
In Friday's quarterfinals, Verdasco meets Ruben Ramirez-Hidalgo; Volandri plays Montanes; Simon faces Lapentti; and Almagro will play Vassallo-Arguello.
Swim Week Miami Beach 2014 [PHOTOS]