"I thought we were poor. It was a disappointing team performance," Sir Alex told MUTV. "Boca pressed the ball and it was something we weren't used to from the Far East games.
"No disrespect to the Far East teams, but that was a real game for us tonight in that sense. We're back in the real world and hopefully we'll come on from this game.
However, Ferguson was pleased with Antonio Valencia's scoring debut.
"There were positive moments though - we were very satisfied with Antonio's first game," he added.
"He had to go back to Ecuador to get his work permit and that meant he missed some of the pre-season work, but he has shown that he has good talent, balance and he's a good athlete. So we have got something to work with there."