They recovered to beat Albania by a comfortable 4-0 margin a month later.
Mexico must now use that experience in the final preparations ahead of the clash with another Balkan team, Croatia on 3 June.
"We have learned that European football is played more strongly than in Mexico and than in the Americas as a whole," Aguirre said.
"They play to a much faster rhythm. So we must find strategies to retain the ball as much as we can and affect them through this, without too much physical contact.
"All the world is talking about the group which includes England, Argentina, Nigeria and Sweden.
"But our group, without quite so much quality, is still very comparable.
"Any of three teams in our group could qualify for the next round.
"The matches against Ecuador and Croatia have to be won no matter what.
"It's all or nothing, so we can come to the match with Italy with the necessary points already in our pockets."