US coach Bruce Arena said on Thursday that the balls used in his team's World Cup match against Portugal were not pumped to the right pressure.
The new World Cup football has received criticism in the build-up to the tournament for being too light, but Arena said the problem against Portugal was down to air pressure.
"I think they have got to do a better job before the games in
making sure all the balls have the right air pressure.
obviously a problem," Arena said.
Fifa confirmed there had been
complaints at the game, and Arena said that Portugal were also not happy.
Fifa communications director Keith
Cooper said. "The balls were replaced. After the game, all the balls were
tested and they were all exactly in conformity with the
specifications laid down by Fifa."
The Fevernova ball, made by Adidas, has come under criticism from the likes of Italy keeper Gianluigi Buffon and Slovenia's Zlatko Zahovic.