John Isner shocked Roger Federer in four sets to secure a 2-0 lead for the United States away to Switzerland in Davis Cup World Group action Friday while holders Spain carved out the same advantage over Kazakhstan in their first-round tie.

Big-serving Isner beat Federer 4-6, 6-3, 7-6, 6-2 to end his opponent's 15-match unbeaten run in Davis Cup singles rubbers and described it as the greatest win of his life.

He had lost his two previous meetings with the Swiss, both on hardcourts, but this time the 17th-ranked Isner spoiled a rare Davis Cup appearance by the 16-times grand slam singles champion with a clinical performance on clay in Fribourg.

"It's one of the greatest wins of my life, no that's wrong, it's the greatest win of my life," said Isner at courtside after the two-hour 39-minute contest.

Mardy Fish had earlier edged Stanislas Wawrinka 6-2, 4-6, 4-6, 6-1, 9-7 as Switzerland's bid to reach the quarter-finals for the first time since 2004 got off to the worst possible start against the team that beat them in the 1992 final.

"The mission was to go out there and not allow an artist a canvas to work with," U.S. captain Jim Courier said of Isner's victory.

The winners of the tie will play away in the last eight against Canada or France, who were tied at 1-1 in Vancouver after Jo-Wilfried Tsonga beat Vasek Pospisil 6-1, 6-3, 6-3 and Milos Raonic got the hosts back on terms with a 6-2, 6-4, 7-5 victory over Julien Benneteau.

Spain began the defence of their title with Nicolas Almagro, their number one in the absence of Rafa Nadal and David Ferrer, and Juan Carlos Ferrero winning in contrasting fashion.

Almagro, had a fairly comfortable 6-3, 4-6, 6-1, 6-1 victory over stubborn Kazakh Andrey Golubev while Ferrero returned to the Davis Cup with a thrilling 6-1, 4-6, 7-6, 4-6, 6-4 win over Mikhail Kukushkin in a gruelling four hour 28 minute contest.

Last year's runners-up Argentina took a 2-0 lead against Germany after David Nalbandian and Juan Monaco saw off Florian Mayer and Philipp Petzschner respectively on Bamberg's indoor clay court.

Monaco dismissed Petzschner 6-3, 6-3, 6-3 as the U.S. Open doubles champion committed 47 unforced errors in a disappointing performance before Mayer lost 2-6, 6-0, 6-1, 7-6 to Nalbandian.

In Hyogo, Japan's Go Soeda, the world number 90, came from two sets down to upset 55th-ranked Ivan Dodig 6-7, 3-6, 6-4, 6-3, 7-5 and open a 1-0 lead over Croatia.

Ivo Karlovic then levelled for the 2005 champions with a 6-4, 6-4, 6-3 success against Kei Nishikori.

Serbia, the 2010 winners who are without world number one Novak Djokovic, are 2-0 up at home to Sweden thanks to a 6-3, 6-3, 6-4 victory for Janko Tipsarevic over Filip Prpic and Viktor Troicki's 6-4, 6-3, 5-7, 6-3 triumph over Michael Ryderstedt.

Austria hold a 2-0 advantage over Russia after Juergen Melzer fought off Igor Kunitsyn in five sets and Andreas Haider-Maurer beat Alex Bogomolov in four in Wiener Neustadt.

Czech Republic also have a 2-0 lead over Italy thanks to Radek Stepanek's battling 4-6, 6-4, 6-3, 3-6, 6-3 win over Andreas Seppi and Tomas Berdych's 6-3, 4-6, 7-5, 6-2 victory against Simone Bolelli.