Roger Federer fell to a shocking 4-6, 6-3, 7-6 (4), 6-2 defeat by John Isner as the United States took a 2-0 lead against Switzerland in their Davis Cup first-round series on Friday.
Isner's usual big serve was backed by a string of booming ground strokes that challenged third-ranked Federer in longer rallies on the indoor clay court.
''I thought he played great,'' Federer said. ''He played it tough and served great when he had to. I just missed a couple more opportunities than he did and that's what cost me the match.''
Federer's upset loss was even eclipsed for drama and tension by a thrilling opening match as Mardy Fish beat Stanislas Wawrinka 6-2, 4-6, 4-6, 6-1, 9-7.
The US can eliminate Switzerland in Saturday's doubles when a scheduled scratch pairing of Mike Bryan and teenager Ryan Harrison are set to face Federer and Wawrinka, the 2008 Beijing Olympics gold medalists.
''It's been a difficult day for us,'' Federer said, adding ''we still have a chance to go through. I'm going to enjoy the challenge.''
A partisan crowd of 7,000 at Fribourg Forum was stunned into silence at Federer's first loss in Davis Cup singles for eight years.
Yet Federer had started in routine fashion, winning the first set without dropping serve.
Isner broke Federer's serve in the sixth game of the second set, but failed to exert any pressure in the third.
Still, Federer couldn't convert break chances in the sixth and eighth games - taking just one of his 12 opportunities in the match - and the set drifted into a tiebreaker.
Isner never trailed, clinching it on his first set point with a subtle stop volley at the net which gave Federer no chance of retrieval.
The fourth set turned on the fifth game when Isner battled back from 0-40 down with three big serves and two blistering forehand winners.
Federer never recovered and Isner reeled off four straight games, ending the match by rifling a backhand winner crosscourt.
''I thought John finished it well,'' Federer said. ''It's always a little bit easier to swing from the hip when you are a break up and two sets to one.''
Isner had lost his two previous encounters with Federer, both on hard courts.
If the 17th-ranked Isner needed any inspiration to take on Federer, he found it in Fish's earlier victory that took 4 hours, 26-minutes, the third-longest Davis Cup singles match involving a U.S. player since 1989 when the competition brought in tiebreakers.
Fish found the reserves to fight back after wasting a match point chance at 5-4 in the decider, and clinched victory six games later with a cushioned, crosscourt volley winner at the net.
''It's certainly up there, there's no doubt about it,'' said Fish, when asked how it ranked among his best wins. ''It's a good win to beat Stan, period. Clay is his best surface, his favorite surface and it's in his home country. I'll take that away, for sure.''
A 95-minute final set saw wild shifts in momentum and emotion, before the eighth-ranked American improved his record to 3-0 against the 28th-ranked Wawrinka.
''He did everything to win,'' Wawrinka said of Fish. ''He played more aggressively in the fifth set.''
