Novak Djokovic, the world's No. 1 player, captured his opening match as expected over John Isner, leaving Querrey needing to win to give the Americans a reasonable chance of advancing in the most significant team event in tennis.
Querrey survived a first-set tiebreaker and then lost the next two sets to Viktor Troicki. But the American came back to win 7-6 (7-1), 3-6, 4-6, 6-1, 6-4.
Djokovic will then face Querry and Isner will take on Troicki in Sunday's reverse singles. The winner of this showdown will take on either Canada or Italy in the semifinals.
Djokovic won the first of Friday's matches on Boise's indoor hard court surface 7-6 (7-5), 6-2, 7-5. Isner put together an early first-set service break against Djokovic and served 17 aces, but he made 54 unforced errors to just 14 for his powerful opponent.
The Querrey-Trocki match took 3 hours, 20 minutes to complete and included 308 points.