- Roger Federer beaten in Davis Cup tie in Switzerland
- John Isner wins in four sets as United States take 2-0 lead
- Mardy Fish saw off Stanislav Wawrinka in earlier match
- Holders Spain leading Kazakhstan 2-0 in Oviedo
Roger Federer suffered a stunning upset defeat to John Isner as the United States took a 2-0 lead Friday in their Davis Cup World Group first round match in Switzerland.
Home favorite Federer was in action for the first time since losing to Rafael Nadal in the semifinals of the Australian Open and could find no answer to an inspired Isner, who won 4-6 6-3 7-6 6-2.
It followed an earlier 6-2 4-6 4-6 6-1 9-7 win for Mardy Fish over Stanislav Wawrinka in the first rubber of the tie.
World No.3 Federer was expected to tie it up on the indoor clay court in Fribourg, which was selected by the Swiss hosts, but Isner, best-known for his marathon match against Nicolas Mahut at Wimbledon, again showed his aptitude on the slower surface.
After dropping the opening set, the American took the next three to close out victory in two hours 40 minutes, ending a 15-match winning streak for Federer in the Davis Cup.
"The way I played today is the way I need to play in all my matches," said Isner after his surprise victory.
"I owe it to Jim Courier (American Davis Cup captain) -- he was on at me to hit all my shots. It's the win of my life."
Fish, despite his higher ranking, was not favored against Wawrinka, but showed his fighting qualities in a four hour 26 minute match.
He played superbly in the fourth set to level the match for the loss of a single game and always looked the stronger in the 16-game decider.
"I lost a couple of long ones in Austin last year, and that feels so bad I just needed to win this one.' Fish told the official Davis Cup website.
Wawrinka and Federer will pair up for Saturday's doubles where they will take on Mike Bryan and teenager Ryan Harrison.
Meanwhile, holders Spain took a 2-0 lead over Kazakhstan after the opening day of their first round tussle in Oviedo.
With World No.2 Rafael Nadal missing the tie for the home team, it was left to Juan Carlos Ferrero and Nicolas Almagro to step up to the plate.
Veteran Ferrero needed five sets to beat Mikhail Kukushkin 6-1 4-6 7-6 4-6 6-4 while Almagro eased past Andrey Golubev 6-3 4-6 6-1 6-1.