The American brothers dropped their first set to Marcel Granollers and Fernando Verdasco 6-7 (3-7), then battled back to take the next three sets 6-4, 6-4, 6-4. The 2-hour, 41-minute match drew the United States to within 2-1 in its Davis Cup clash with Spain.
The Bryans improved their Davis Cup record to 18-2.
Sunday's decisive reverse singles will feature Fish against Ferrer and Roddick battling Lopez. The winner will face France in the September semifinals.
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