Paul Capdeville gave Chile a lift with a 6-7 6-7 7-6 7-6 6-4 upset victory over John Isner to help his country split the opening day of their Davis Cup first-round tie on Friday.
After Andy Roddick put the US ahead with a 6-2 4-6 6-3 6-4 win over Nicolas Massu in the first of five matches, the 165th ranked Capdeville defeated Isner, who is ranked 133 places above him.
The first four sets of the endurance test which went four hours and 22 minutes, were decided by tiebreaks and Capdeville battled back from 2-0 down to take the match to a fifth set.
The Chilean then grabbed the first break of the match to lead 5-4 and then served out.
World number eight Roddick had his work cut out for him against a Massu, who was backed by a passionate home crowd.
Roddick broke in the decisive fifth game but then Massu lead 40-0 again before Roddick rallied and on the fifth break point the American won thanks to a forehand error from Massu followed with a trademark big ace.
"I don't know that I was ever comfortable," said Roddick.
"An away tie on clay in the Davis Cup with the crowd against you isn't a recipe for settling in and feeling perfect but it is a recipe for a dogfight and I think that is what it was and I am always happy to be in one of those."