Klinsmann's side were seconds away from booking their place in the last 16 of the competition as they led Portugal 2-1, but a last-minute equaliser from Silvestre Varela means that the USA will need a point at the least to qualify from the group.
He told BBC Sport: "Germany played yesterday and so have more time to recover. We played in the Amazon and they haven't had to travel much.
"Everything has been made easy for the favourites, whereas we have to struggle to go through, but that is what we will do."
The USA take on Germany on Thursday at the Arena Pernambuco.