Ghana wrapped up preparations for the World Cup in Brazil with a 4-0 rout of South Korea on Saturday, with Marseille forward Jordan Ayew's hat-trick inspiring the demolition in Miami.
But Bradley said international friendlies counted for little ahead of the pair's Group G clash in Natal on Monday.
"It would be easy to look at the end and say,'4-0, what a performance'," the Toronto FC player told reporters on Tuesday.
"But still you know it's a warm-up game, and regardless of how the game went last night, we have a lot of respect for Ghana.
"In general, I think it's hard to take much from any of these warm-up games.
"The teams are trying different things, different guys get put on the field in different spots."
Bradley also said he would not get carried away by the USA's form heading into the tournament, with Jurgen Klinsmann's men winning their past three warm-up games against Azerbaijan (2-0), Turkey (2-1) and Nigeria (2-1).
"It's nice to get the win, but the reality is that these games mean nothing now," Bradley said.
"You use them for what they are in the moment and you use them to sharpen up, to build some confidence, to get everybody even more fit. But the second they're over, you move on."
Meanwhile, USA team-mate Matt Besler said he is determined to make the most of his opportunity at the World Cup, having missed out on a ticket to South Africa four years ago.
"When you get in your first cap, it's great and it's a big moment, but after the game it's what's next," said the Sporting KC defender, who has earned 17 caps since making his international debut against Canada in January last year.
"You make the World Cup team and it's great moment in your career, but then it's what's next. It's the Ghana match.
"It's just having that attitude of wanting to achieve the next thing in your career."
The USA will also come up against European powerhouses Portugal (June 22) and Germany (June 26) in Group G.
