The Russians shocked big-name sides throughout Europe en route to last season's UEFA Cup success, and their menace is no secret to the Reds' coaching staff.
"The press are saying we’re big favourites, but that doesn’t come into our preparation for the game," Sir Alex told his pre-match press conference. "Our preparations for the game go towards Zenit St Petersburg, their style of play and their tactics.
"Going on our analysis, even away from home, there are four players in the box on the end of every cross. They’re very good at getting players into the box.
"I’m sure that will be exactly the case tomorrow, the important thing is that we hold our concentration and make sure we deal with that, then express our own game and enjoy it."
Sir Alex will be locking horns with former Rangers manager Dick Advocaat in Monaco, and the United boss has great admiration for the Dutchman's sparkling career.
"The Dutch are traditionally good travellers in football," he said. "It’s a great asset to have, because football is the important thing and he has proved himself as a very competent and successful coach – no matter where he’s been."