Roger Federer slumped to his first Davis Cup defeat in nine years on Friday when he was shocked 4-6, 6-3, 7-6 (7/4), 6-2 by John Isner as the United States opened up a 2-0 lead over Switzerland. World number three Federer, playing a World Group first round tie for the first time in eight years, saw his 15-match winning streak in the competition ended by the giant Isner on the indoor clay courts at Fribourg.
Isner secured victory with three return winners as the 32-time Davis Cup champions moved closer to a quarter-final spot. Federer insisted that he and Stanislas Wawrinka, the Olympic doubles champions, can still pull the tie around by winning Saturday's doubles against Mike Bryan and Ryan Harrison.
"I played a good match considering the altitude and the fact that it was my first match on clay since the French Open," said Federer. Defending champions Spain, who are without Rafael Nadal, were comfortably placed at 2-0 ahead of Kazakhstan in Oviedo. Veteran Juan Carlos Ferrero clawed out a 6-1, 4-6, 7-6 (7/2), 4-6, 6-4 win over Mikhail Kukushkin before Nicolas Almagro defeated Andrey Golubev 6-3, 4-6, 6-1, 6-1. Nadal is skipping the tournament to concentrate on the Grand Slams as well as the defence of his Olympic title.
World number one Novak Djokovic is also absent from 2010 champions Serbia's tie in Nis against Sweden. But he wasn't missed as Janko Tipsarevic beat Filip Prpic 6-3, 6-3, 6-4 and Viktor Troicki saw off Michael Ryderstedt 6-4, 6-3, 5-7, 6-3 for a 2-0 lead.
In Bamberg, last year's beaten finalists Argentina put a foot in the quarter-finals when they opened up a 2-0 lead against Germany.
Juan Monaco beat Philipp Petzschner 6-3, 6-3, 6-3 before David Nalbandian battled back to defeat Florian Mayer 2-6, 6-0, 6-1, 7-6 (7/5). In Hyogo, Ivo Karlovic fired 18 aces to claim a straightforward 6-4, 6-4, 6-3 victory over Australian Open quarter-finalist Kei Nishikori as Croatia pulled level at 1-1 with Japan who are back in the World Group for the first time in 26 years. Japanese number two Go Soeda had earlier stormed back from two sets down to beat Ivan Dodig 6-7 (3/7), 3-6, 6-4, 6-3, 7-5.