John Isner will play top-ranked Novak Djokovic in the first match Friday of the Davis Cup quarterfinal between the United States and Serbia.
Sam Querrey, the top-ranked American at No. 20, will face Viktor Troicki in the second match, based on the draw announced Thursday in Boise, Idaho.
''Our guys are feeling good and have been practicing well,'' said U.S. captain Jim Courier, during the draw ceremony at the Boise Depot on Thursday. ''Going up a team as accomplished as the Serbs is a big challenge and we look forward to that challenge.
''We're going to have to play our best tennis, no holds bar, to get through this weekend from the first ball to the last ball.''
The top-ranked doubles team of Bob and Mike Bryan will take on Nenad Zimonjic and Ilija Bozoljac on Saturday.
Courier expects Bozoljac will be benched in favor of Troicki prior to the doubles match Saturday.
In reverse singles on Sunday, Querrey and Djokovic will play the first match followed by Isner and Troicki.
Djokovic holds a slight 2-1 winning record over Isner, but the American won their last match in the 2012 Indian Wells semifinal.
''Our preparation has been great and captain Courier has been on us to make sure we're making all the right decisions,'' Isner said. ''Sam and I are anxious for tomorrow.
''We're both going to have to play well if we want to give our team a lead tomorrow. We have to go out there and believe we're going to be good enough.''
Djokovic leads Querrey 5-1 in previous matches, including a straight sets win in the Indian Wells third round last month.
Troicki holds a 3-1 lead over Isner, but the two have not played since 2011.
Djokovic is carefully shrugging off the suggestion that his presence on the team makes Serbia the favorite nation during the weekend.
''I think there is no clear favorites in this competition, especially in later stages of quarterfinals,'' Djokovic said. ''USA is always going to be a difficult opponent, especially if they're choosing the conditions and location of play.
''They have chosen Boise, that has over 800 meters altitude that can help the service. We all know that John and Sam possess great serves, as well as Mike and Bob.''
Djokovic is coming off being upset 6-2, 6-4 in the Sony Open fourth round by then 34-year-old Tommy Haas of Germany last week, but he insists he's put that match behind him.
''I definitely didn't want to lose that early in the tournament,'' Djokovic said. ''Still, he (Haas) played a better match.
''I played I think the worst match that I had last three years. But I had more time to prepare here.''
This is only the second time that the U.S. and Serbia have met in Davis Cup competition.
The last time they played, Serbia defeated the U.S. 3-2 in the 2010 World Group first round encounter in Belgrade. The Serbians went on to win their only Davis Cup title in 2010.
Idaho is the 34th U.S. state to host a Davis Cup tie.
The U.S. has won a record 32 Davis Cup titles, but has not been dominant in recent years. The last two times the U.S. won the Davis Cup was in 1995 (U.S. defeat Russia 3-2 in final at Moscow) and 2007 (U.S. defeat Russia 4-1 in final at Portland, Ore.).
The winner of the quarterfinal tie between the U.S. and Serbia will face the winner of the quarterfinal tie between Canada and Italy taking place in Vancouver, British Columbia, this weekend.
