02/10/2012 04:07 EST | Updated 04/11/2012 05:12 EDT

Isner shocks Federer, US leads Switzerland 2-0 in Davis Cup

FRIBOURG, Switzerland - John Isner jolted Roger Federer with his big serve and booming groundstrokes Friday, winning 4-6, 6-3, 7-6 (4), 6-2 to give the United States a 2-0 lead against Switzerland in the first round of the Davis Cup.

Isner challenged the Swiss star in long rallies on the indoor clay court, sending Federer to his first loss in Davis Cup singles in eight years.

"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."

The upset was preceded by a riveting opening singles match, with Mardy Fish outlasting Stanislas Wawrinka 6-2, 4-6, 4-6, 6-1, 9-7.

The U.S. can eliminate Switzerland in doubles in the best-of-five series Saturday. Mike Bryan and teenager Ryan Harrison will face Federer and Wawrinka, the 2008 Beijing Olympics gold medallists .

Seven other first-round series in the top tier of Davis Cup were contested Friday. Croatia and Japan were tied 1-1, Ahead 2-0 were Serbia (vs. Sweden), Austria (vs. Russia), Argentina (vs. Germany) and Spain (vs. Kazakhstan). The other matchups were: Czech Republic vs. Italy and Canada vs. France.

A partisan crowd of 7,000 at Fribourg Forum was stunned into silence by Federer's loss. He started in routine fashion, winning the first set without dropping serve. Isner broke in the sixth game of the second set, but failed to exert any pressure in the third.

Still, Federer couldn't take capitalize on break-point chances in the sixth and eighth games — winning just one of his 12 opportunities in the match — and the set drifted into a tiebreaker.

Isner never trailed and clinched on his first set point with a subtle volley at the net that left Federer no chance.

The fourth set turned on the fifth game when Isner rallied from 0-40 down with three big serves and two blistering forehand winners.

Federer never recovered. 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 17th-ranked Isner needed any inspiration for his match with Federer, he found it in Fish's earlier 4-hour, 26-minute victory — the third-longest Davis Cup singles match involving a U.S. player since 1989 when the competition brought in tiebreaks.

Fish managed to rally after wasting a match point at 5-4 in the deciding set and won six games later with a 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 favourite surface and it's in his home country. I'll take that away, for sure."

A 95-minute final set included 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. "He played more aggressively in the fifth set."