Portugal's Nani has admitted that he is expecting a strong challenge from the US when the two sides meet in Group G at the World Cup.

Despite being considered underdogs to reach the knockout stages after being drawn alongside Germany, Portugal and Ghana, Nani believes that Jurgen Klinsmann's side will approach their second group fixture on June 22 full of confidence.

"We expect a strong team with a good mentality," the Manchester United winger told reporters. "They have a lot of confidence.

"We know that we have to do our best and prepare ourselves to play that game at the best that we can do."

Portugal begin their campaign against Germany on Monday, with the US meeting Ghana on the same evening.