World No. 1 Novak Djokovic beat big-serving John Isner in straight sets to give Serbia a 1-0 lead over the United States in their Davis Cup World Group quarter-final on Friday.
Djokovic defeated Isner 7-6 (7/5), 6-2, 7-5, recovering from an early break in the opening set and taking control from there.
Djokovic saved the only break point he faced in the third set, and gained the break he needed in the 11th game to give himself a chance to serve out the match on the indoor court at Boise's Taco Bell Arena.
He finished off the two-hour encounter with a love game.
American Sam Querrey was trying to get the hosts back on terms when he took on Viktor Troicki in the second singles match in the best-of-five tie.
The winner will take on the victor of the quarter-final tie between Canada and Italy in Vancouver.