James Blake beat Mikhail Youzhny 6-3 7-6 6-7 7-6 to give the United States a commanding 2-0 lead over holders Russia in the Davis Cup final in Portland, Oregon.
Blake, who lost to world number 19 Youzhny in their only previous meeting in last year's semi-final, claimed victory in a rollercoaster contest lasting three-and-a-half hours and enthralling a capacity home crowd at the Memorial Coliseum.
The American world number 13 failed to serve out for the match when leading 5-4 in the fourth set, but he held his nerve to clinch the tiebreak 7-3 when Youzhny netted a forehand.
"He played great and he's got a lot more experience than me in situations like this," Blake said.
"For me to come through is a big moment for me and for the team. It's definitely my best performance. And playing at home makes it a lot more fun."
Earlier, American number one Andy Roddick had outclassed Dmitry Tursunov 6-4 6-4 6-2 in the opening rubber to put the hosts ahead.
Blake's victory puts the United States on the brink of a record 32nd Davis Cup title with the Bryan brothers, Bob and Mike, due to take on Nikolay Davydenko and Igor Andreev in Saturday's doubles.
The Bryans, winners of five grand slam titles together, have lost just one doubles match in 13 Davis Cup appearances.
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