Nicolas Almagro thumped Jurgen Melzer 6-2 6-2 6-4 and David Ferrer thrashed Andreas Haider-Maurer 6-1 6-3 6-1 to put the hosts in command.

The clay kings, who have won their last 22 home Davis Cup ties and are bidding for a fourth title in five years, appear to have far too much quality for their opponents despite the absence of world number two Rafa Nadal.

Almagro and Ferrer ensured he probably will not be missed too much as they put Spain on the verge of a September semi-final against France or United States.

"That was possibly my best match in Davis Cup," Almagro, the world number 12, said. "I knew that I was going to be nervous and I was tense at the start and so were the first three or four games.

"But I threw off the shackles and then the tennis started to flow."

Ferrer said his match had been a lot easier than he expected.

"He (Haider-Maurer) made a lot of mistakes and I was able to play my game without ever really getting into a rhythm," the world number five said.

"Let's hope we can wrap things up tomorrow (in the doubles) but it's going to be a tricky match."

Spain captain Alex Corretja said he could have to deploy Almagro or Ferrer to partner Marcel Granollers on Saturday as Marc Lopez was carrying a back injury and may not be able to play.

France and United States were locked at 1-1 after the opening singles on Friday, Jo-Wilfried Tsonga leading the charge for the hosts by despatching teenager Ryan Harrison 7-5 6-2 2-6 6-2.

However, world number 11 John Isner brushed aside Gilles Simon 6-3 6-2 7-5 to level the tie.

Simon, who has never beaten Isner, was called up last week to cover for the injured Gael Monfils but was unable to cope with the American's huge serve.