Novak Djokovic got Serbia off to a hot start, but American Sam Querrey's gritty victory over Viktor Troicki saw the United States pull level on the opening day of their Davis Cup World Group quarter-final tie.
World No. 1 Djokovic beat big-serving John Isner in straight sets in the first singles match, recovering from an early break in the first set en route to a 7-6 (7/5), 6-2, 7-5 triumph.
The Serbian player saved the only break point he faced in the third set -- in the second game -- and broke Isner at love for a 6-5 advantage.
He served out the match with a love game, wrapping it up in two hours with a backhand winner that sent him dancing over to celebrate with his teammates.
Isner had made a quick start, breaking Djokovic for a 2-1 lead in the first set and holding for 3-1. But Djokovic found his rhythm on the indoor hard court in the Taco Bell Arena in Boise, which sits at an altitude of about 800 meters (2,600 feet), and broke back to level the set at 3-3.
Djokovic delivered a second-serve ace to take a 4-1 lead in the tiebreaker and claimed the first set on his third set point when Isner knocked a backhand long.
The Serbian applied the pressure early in the second set, breaking Isner in the third game and widening the gap with another break in the seventh.
Tasked with getting the best-of-five tie back on terms, Querrey started strong, winning the first set and going up an early break in the second.
But he let that advantage slip away and after dropping the second and third sets had to dig deep for a 7-6 (7/1), 3-6, 4-6, 6-1, 6-4 victory.
It was just the second five-set match victory of Querrey's career, and he finished it in style, breaking for a 5-4 lead in the fifth set and serving it out with a love game.
Serbian captain Bogdan Obradovic had called on Troicki for singles duty after world No. 10 Janko Tipsarevic opted out of the tie.
The winner will take on the victor of the quarter-final tie between Canada and Italy in Vancouver.
Serbia's run to the 2010 Davis Cup title included a victory in their only other meeting with the United States, who have lifted the trophy 32 times.
US captain Jim Courier has a formidable weapon at his disposal for Saturday's doubles, when he'll send Bob and Mike Bryan against Nenad Zimonjic and Ilija Bozoljac.