Either the Red Devils will overturn a first-leg deficit inflicted on home soil and reach the Europa League quarter-finals or they will be eliminated from a second UEFA competition in a single season, which would be an equally new experience for Ferguson and his men.
"March has always proved an important month for us," he said. "Historically and in general it has been a good month. Now is the time you have to kick on. There's no looking back. It's about looking forward and trying to make sure you win all your games."
Some wins are easier to achieve than others though.
And on the evidence of last week, United have a tough task if they are to overcome Bilbao, who earned such praise for their performance at Old Trafford.
Since then, Anderson has been ruled out for "four or five weeks" with a hamstring strain, Nani has sat out a couple of matches, Phil Jones has picked up a flu virus and Chris Smalling is still to fully recover after splitting his head open on England duty last month.
It just represents the latest setbacks in an injury-ravaged season in which United have still managed to find themselves at the top of the Premier League with 10 games remaining.
"We have done really well to hang in there," said Ferguson. "That is more or less what we have done no matter what the team has been.
"For instance (tomorrow night), with (Phil) Jones and (Chris) Smalling not available that's a door slamming in the face again. But we keep carrying on and it does point to a resilience in the team that is really admirable. They have done exceptionally well. It's an achievement in the sense of they're still banging in there in the league.
"Yes, there was the disappointment in the Champions League but we still can win this game tomorrow and I think the players believe that."
Source: PA
Source: PA