Aguirre begins his second stint on Saturday when Mexico, currently out of the direct qualifying places for the World Cup finals, visit El Salvador's Cuscatlan stadium, where visiting teams can be assured of a hostile reception.
It is exactly the sort of intimidating cauldron where Mexico struggled under Aguirre's predecessor Sven-Goran Eriksson, as they lost twice in Honduras and once in Jamaica.
Mexico's players believe they have already sensed a difference between Aguirre and his phlegmatic predecessor.
"Javier's arrival has motivated us, it has made us change our way of thinking and I think we're going to be in the right frame of mind for Saturday's game," said striker Nery Castillo.
"Aguirre has taken away all our doubts," added midfielder Andres Guardado.
"Now, we have to go and play with a different attitude, especially given our quality on the pitch where, man for man, we know we are better."
United States, who are second with seven points from four games, face Honduras in Chicago hoping to bounce back from Wednesday's dismal 3-1 defeat in Costa Rica.
"Honduras are a talented team," said defender Oguchi Onyewu.
"We have a quick turnaround time between the games, so we have to do what is necessary to be prepared and have a better result. Right now we have to learn from our mistakes."
Leaders Costa Rica, who have nine points, visit bottom team Trinidad and Tobago in Saturday's other game.
