The reigning English Premier League champions kick off the Herbalife World Football Challenge on Wednesday against the MLS outfit in Boston and Ferguson is well aware what teams in the USA are capable of after losing in Kansas City last year.
"As we experienced last season and with the rise in United States soccer, we're expecting a difficult game," Ferguson told MLSsoccer.com during a press conference held on Monday afternoon.
"Last season, all of the games were very, very tough. We look forward to it. We hope we do ourselves justice, but, most important, we hope that we take a step forward in terms of our fitness, which is one of the reasons why we are here."
But Ferguson made it clear that his players would still be a long way off their fittest as they only reunited for pre-season training last week.
"It's our first game and it doesn't seem so long ago that we played in the European final (loss to Barcelona)," Ferguson added.
"The players should be well-rested, but our preparation isn't 100 percent at the moment because we only started on the fourth of July with medical testing and then training since then."