NASHVILLE, Tenn. (AP) — The United States has a big advantage at least in world rankings, and John Isner and Sam Querrey have given the Americans a 2-0 lead in the Davis Cup quarterfinals over Belgium. First, Isner beat Joris De Loore 6-3, 6-7 (4), 7-6 (8), 6-4, and Querrey followed with a straight sets victory, beating Ruben Bemelmans 6-1, 7-6 (5), 7-5 Friday night to put the U.S. a victory away from reaching the semifinals for the first time since 2012. "We also know the job isn't done," U.S. captain Jim Courier said.