Canada had put the short-handed Spaniards on the verge of elimination when Milos Raonic and Frank Dancevic picked up singles wins Friday in the best-of-five competition.
But Granollers and Lopez staved off elimination with a 4-6, 6-4, 6-7 (4-7), 6-3, 6-2 victory over Canada's tandem of Daniel Nestor and Vasek Pospisil.
Sunday's singles matches will pit Granollers against Raonic and Albert Ramos against Dancevic.
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