Italy fear that the United States' determination to keep their World Cup hopes alive will make them dangerous opponents here in Saturday's Group E match.
The Americans were trounced 3-0 by the Czech Republic in their opening game and are in danger of an early exit, while victory for the Italians could be enough to earn them a last 16 place.
"We won't be underestimating the United States because they have to win against us or they're out," said Andrea Pirlo, scorer of Italy's first goal in their 2-0 win over Ghana which stretched their unbeaten run to 19 matches.
"They were well beaten by the Czechs in their first match, but that will only make them more determined to get the three points. They know that they have to play the game of ther lives."
Italy coach Marcello Lippi admitted he was surprised by the ease with which the Czech Republic beat the Americans.
"I was expecting a closer match because the USA have made giant strides in the last five years," he said.
"They reached the quarter-finals of the World Cup four years ago and came here full of confidence."
Defender Gianluca Zambrotta is in line for a recall for Italy after recovering from the left thigh strain which kept him out of the Ghana match.
Tenacious midfielder Gennaro Gattuso, also absent against the Ghanaians, is making good progress after feeling a recurrence of a right leg injury and could play some part.
USA coach Bruce Arena said playing Italy is just the sort of challenge his team needs to show their true character.
"This is the moment to shine, to step up and show what you're about," he said. "I think they are ready to give a good effort."
Giving no hints of the line-up changes he plans for Saturday's match, Arena said he expects his players to answer their wake-up call.
"All we did was lose a game. The challenge in any sport is how you respond," he said.
"Naturally there is over-reaction in the short term. If there is any kind of quality in the team, they'll bounce back."
With Arena threatening to wield the axe, competition for places in the USA team has been fierce.
"Guys who weren't on the field want to be on it, guys who were want to prove they should stay on it," said midfielder Bobby Convey.
"Everyone knows we have to do better. Everyone was excited in training. The coach said he is going to make changes. That gives everyone an opportunity, and when you get an opportunity you have to take advantage of it."
Landon Donovan and DaMarcus Beasley are expected to retain their places for the Americans, despite being publicly criticised by Arena.
Italy, who won the World Cup in 1934, 1938 and 1982, have played the United States eight times, winning six and drawing two.
The teams met in the first round of the 1990 World Cup, with tournament hosts Italy winning 1-0 in Rome.
Gianlugi Buffon, Cristian Zaccardo, Alessandro Nesta, Fabio Cannavaro (capt), Gianluca Zambrotta, Simone Perrotta, Andrea Pirlo, Daniele De Rossi, Francesco Totti, Alberto Gilardino, Luca Toni: Coach: Marcello Lippi
Kasey Keller, Steve Cherundolo, Eddie Pope, Oguchi Onyewu, Carlos Bocanegra, Bobby Convey, Claudio Reyna (capt), Pablo Mastroeni, Clint Dempsey, Landon Donovan, Brian McBride: Coach: Bruce Arena
Jorge Larrionda (URU)