MADRID, Sept. 16 (Xinhua) -- David Ferrer won the first singles rubber on Sunday to give Spain an unassailable 3-1 lead over the USA in the semifinal of the Davis Cup tennis tournament which was played in the northern city of Gijon.

Ferrer overcame the loss of the first set on a tiebreak 6-7 (3), to defeat John Isner 6-7, 6-3, 6-4, 6-2 and give the Spanish a winning lead.

Isner began the match with hopes of leveling the tie after the Bryan brothers had beaten Marcel Granollers and Marc Lopez in Saturday's double tie to make the semifinal 2-1 following Friday's singles.

However, the big serving American quickly ran out of steam and Ferrer was soon able to impose the form which took him to the semifinal of the US Open just over a week ago.

It is the ninth time that Spain, who won the competition last year, have reached the final of the Davis Cup, although the reigning Champions will have to play the final away to either Argentina or the Czech Republic, who are currently disputing the other semifinal in Buenos Aires.