Players who will make up the next generation of American soccer -- including star Freddy Adu -- completed group play unbeaten and advanced to the Round of 16, where they will meet an as yet undetermined opponent Wednesday in Toronto.
The United States won Group D with seven points, while Poland, a 6-1 loser to the Americans earlier in the week, finished second with four points. Brazil, one of the pre-tournament favorites, had three points and must wait two days to see if it will be one of the four third-place teams that move on to the knockout round.
Altidore put the United States in front in the 25th minute and scored the winning goal in the 81st minute.
Chris Seitz was outstanding in goal for the Americans during a second half in which Brazil mounted almost constant pressure.