Alessandro del Piero and Amauri had Juve 2-0 ahead before Ruud van Nistelrooy managed to pull one back for the visitors.
"I do not think it has come as a surprise the way Juventus played," said Schuster. "The surprise is how we started the game.
"In other games we've started well, but this time we failed to do so.
"We must remember that whatever Juve's form, they're in the Champions League on merit and that aggression they showed was the least we could have anticipated from them.
"However, soon we took control of the game, the ball."
Schuster added: "The feeling inside the dressing room is that now we must win the return game in two weeks time. That's all. It's clear."