The doubles pairing of Mike and Bob Bryan kept the American hopes alive of reaching the Davis Cup final as they achieved a hard-fought win over the Spanish pairing of Marcel Granollers and Marc Lopez.
The Bryan brothers went into the game Saturday knowing that defeat would qualify the Spanish for the final following Friday's wins for David Ferrer and Nicolas Almagro in the first two singles pairings, reports Xinhua.
They American twins won the first set 6-3, before Granollers and Lopez hit back to take the second 3-6.
The third set was a tense affair and looked set to go to a tiebreak before the Bryans broke serve in the final game and they then came down from 4-1 down in the fourth set to claim it 7-5 and win the match 6-3, 3-6, 7-5, 7-5 in three hours and 39 minutes.
Sunday sees the final two singles matches and with Ferrer and Almagro on form, Spain are still favourites to reach the final where they would play with Argentina or the Czech Republic.