Rafael Nadal shrugged off a bout of jet-leg to beat Nicolas Kiefer before David Ferrer outpunched Philipp Kohlschreiber to give Spain a 2-0 lead over Germany on day one of their Davis Cup quarter-final.
Nadal, who has had trouble sleeping since flying in from Miami at the start of the week, made a sluggish start on the indoor hard court but edged an 88-minute first set 7-5 on the tiebreak and went on to win comfortably 7-6, 6-0, 6-3.
Ferrer also started slowly, losing the first set against the German number one before coming through 6-7, 6-3, 6-4, 6-2.
Germany, who won the last of their three Davis Cup titles in 1993, now need to win Saturday's doubles to keep the tie alive.
Kohlschreiber will team up with Philipp Petzschner, as Fernando Verdasco and Feliciano Lopez look for the third point to send Spain, winners in 2000 and 2004, into the semi-finals.
Nadal missed seven break points in the first game alone and later wasted a chance to serve out for the set.
He fell 4-2 behind in the tiebreak before suddenly upping his game, helped by an unrelenting stream of unforced errors from the 30-year-old Kiefer, back in the Davis Cup after an absence of more than two years.
He broke Kiefer's first service game in the second set, after an inexplicable overhead mistake from the German, and after that it was all too easy as he romped through and took the first of three match points with a fizzing forehand from deep.
"It was a shame I didn't take one of the break points because that would have made it easier," Nadal said. "It was tough but I think having a start like that was good for me."
He added: "I was having to take tablets to get to sleep but I got off okay last night, although I did wake up once. I noticed the tiredness at one or two moments but it was no problem really."
Kohlschreiber looked in great form at the start of the second rubber and gave the home crowd hope when he took the first set 7-3 on the tiebreak.
The German needed treatment to his back and leg muscles in the second set, though, and Ferrer sensed his chance.
The Spaniard, ranked fifth in the world, built up a 5-0 lead and survived a wobble to take the set in 40 minutes, serving out at the second attempt.
He moved two breaks ahead at the start of the third set too, and again fought off a Kohlschreiber comeback to win it 6-4.
Ferrer took the first of two break points to move 2-1 ahead in the fourth and he improved that to 5-2 before serving out for victory in three hours 11 minutes.