Spain surge into lead against U.S. in Davis Cup semis

(CNN) -- Spain took a giant step towards the Davis Cup final winning both singles matches in their semifinal against the U.S. in Gijon on Friday.

In the absence of an injured Rafael Nadal, it was David Ferrer who got the defending champions off to a perfect start on the clay against world No.26 Sam Querrey.

The world No.5 lost the opening set but quickly reasserted his authority over Querrey, overrunning the American in the following three sets to win 4-6 6-2 6-2 6-4.

"It was a hard match, difficult at every moment. Querrey played a very good match but in the end I was up to it," Ferrer said.

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Ferrer was followed on court by Nicolas Almagro and John Isner who played out a thrilling five-set match.

The match ebbed and flowed with neither player able to grab the momentum for long, but it was the Spaniard who got over the line, much to the delight of a patriotic home crowd.

Isner fought bravely to deny Almagro three match points in the ninth game of the deciding set, before the world No.12 sealed victory with a fourth in the 12th to win 6-4 4-6 6-4 3-6 7-5.

"It was very tough. I knew everything about John Isner well. I think he served really good. I didn't feel very comfortable at the court when he was serving. But we are happy because it's Friday and we're 2-0 up," Almagro said.

Meanwhile in the other semifinal, Juan Martin del Potro made the perfect start for Argentina against the Czech Republic in Buenos Aires.

Despite nursing an injured wrist, the world No.8 trounced Radek Stepanek 6-4 6-4 6-2 at the Parque Roca stadium.

"It was very difficult to play with a hurt wrist, but the crowd was fantastic. I am very passionate about playing for my country. I like to give them a good show," del Potro said.

Argentina, who were runners-up to Spain last year, looked on course for a 2-0 lead heading into Saturday's doubles when Juan Monaco took a two sets to one lead in the other singles match against Tomas Berdych.

But the world No.6, who beat Roger Federer at the U.S. Open last week before losing to Andy Murray in the semifinals, produced an inspired comeback to keep the Czechs firmly in contention for their second final in four years.

Berdych took the first set comfortably enough 6-1, before Monaco, cheered on by home support, stormed back into the match winning the next two sets 6-4 6-1.

But Berdych's fighting spirit saw him take the final two sets 6-4 6-4 to leave the teams tied at 1-1.

Saturday's doubles matches see Argentine pairing Carlos Berlocq and Eduardo Schwank take on Ivo Minar and Lukas Rosol -- who dumped Rafael Nadal out of Wimbledon in June.

Spain can book a place in the final if Marcel Granollers and Marc Lopez can upset world No.1 doubles pair, Bob and Mike Bryan.

Despite the deficit, U.S. captain Jim Courier tried to remain upbeat about his team's chances.

"I like our team and I'm very happy with the team we have here. We will miss Andy Roddick but things change and we have to change with them," Courier said, DavisCup.com reported.

"And we'll be ready for Sunday. Tomorrow isn't guaranteed, we have to come and win that (doubles), but John and Sam will be ready for Sunday," he added.