Gimeno-Traver, seeded seventh, ousted Albert Montanes 6-4, 6-4 in their second-round meeting. It was only the second match victory of the year for Gimeno-Traver, who is without a championship in his eight-year pro career.
Nadal will be waiting in the quarterfinals after returning to the courts with a victory Wednesday. He had not played since last year's Wimbledon Championship due to a knee injury.
Third-seeded Jeremy Chardy also advanced Thursday by defeating Christian Garin 4-6, 6-3, 6-2. Chardy's quarterfinal opponent will be No. 6 seed Paolo Lorenzi, who was a 6-4, 6-4 winner over Tommy Robredo.
In other second-round action Thursday, Horacio Zeballos took out Pablo Andujar 6-3, 6-3 and Albert Ramos rallied to defeat Filippo Volandri 6-7 (5-7), 6-3, 7-5.