Montanes' winning score was 6-2, 7-6 (7-2).
In other first-round matches, Daniel Gimeno-Traver beat fellow Spaniard Santiago Ventura 7-6 (9-7), 6-1 and Ricardo Mello of Brazil took down Paolo Lorenzi of Italy 6-2, 7-5.
The top seed, Juan Carlos Ferrero of Spain, begins play Tuesday.
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