The defeat means Patrick McEnroe's U.S. team face a relegation playoff later this year to maintain their record of playing in the World Group every year.
In response to the problem, the U.S. Tennis Association (USTA) has charged PatrickMcEnroe with developing its elite young players, combining this role with captaining their Davis Cup team.
"We've let our best kids play practice sets with the green ball, and every time we've done that the coaches say they're playing a better brand of tennis, " said PatrickMcEnroe, the USTA's general manager of player development.