Ferrer beats Isner to help Spain enter final
World number five Ferrer had to fight from a set down on the clay in the northern Spanish city, coming through 6-7, 6-3, 6-4, 6-2 against the 10th-ranked Isner for his 16th victory in 16 singles rubbers on clay.
On Saturday, Bob and Mike Bryan fought off a challenge from Marcel Granollers and Marc Lopez to win their doubles rubber 6-3, 3-6, 7-5, 7-5.
Meanwhile, Czech Republic's path to the final was wide open after they won the doubles on Saturday and Argentine Juan Martin del Potro pulled out of the reverse singles in Buenos Aires.
World number eight Del Potro almost withdrew from the semifinal at Parque Roca earlier this week due to pain in his right wrist.
Del Potro opened up for Argentina with a three-set victory over Radek Stepanek on Friday before world number six Tomas Berdych overcame Juan Monaco in five sets to level the tie at 1-1. Berdych and Stepanek then teamed up on Saturday to win the doubles 6-3, 6-4, 6-3 against Berlocq and Eduardo Schwank.
Russia’s men were eliminated from the elite group of tennis playing nations for the first time on Saturday, falling to a 0-3 defeat against Brazil in their Davis Cup World Group play-off in Sao Paulo.
Russia’s lowest-ranked team in decades put in a lacklustre performance on the clay courts of San Jose do Rio Preto, with Alex Bogomolov Jr and Teymuraz Gabashvili losing the decisive doubles in straight sets to Marcelo Melo and Bruno Soares 5-7, 2-6, 6-7 (5-7).
Results: At Gijon: Spain bt US 3-1 (On Sunday: David Ferrer bt John Isner 6-7 (3-7), 6-3, 6-4, 6-2; On Saturday: Marcel Granollers/ Marc Lopez lt to Bob Bryan/ Mike Bryan 3-6, 6-3, 5-7, 5-7).
At Buenos Aires: Argentina trail Czech Republic 1-2 (On Saturday: Carlos Berlocq/ Eduardo Schwank lt to Tomas Berdych/ Radek Stepanek 3-6, 4-6, 3-6).