The German side stunned holders Inter 5-2 in the first leg of their quarter-final at the San Siro and need to produce something similar to make amends for a woeful performance at home to United last week.
"Tomorrow we will show we can play better than we did last week and that we have learnt our lessons," Schalke coach Ralf Rangnick told a news conference on Tuesday.
"In football you can get the chance so we will see what happens... when we played in Milan against Inter people didn't give us much hope either."
The Bundesliga team's task is immense at a stadium where United have not lost for more than a year and have conceded only three goals in Europe this season.
United repeatedly tore apart Schalke's defence last week and on home soil they could prove even more devastating, even if manager Sir Alex Ferguson is resting players ahead of Sunday's key Premier League match against Chelsea.
VISA PROBLEMS
But with Schalke having already overcome problems travelling to Manchester, with the team delayed in Germany for a couple of hours because of visa issues affecting some players, they are showing no signs of giving up without a fight.
"I think we have to be well organised in the first 10 minutes and then we have to take our chances when they're presented, even if there are just two minutes left," Rangnick said.
"You think of Manchester United and the Champions League win when they came back to win 2-1," he added, referring to the English club's stunning 1999 final victory over Bayern Munich which came after two stoppage-time goals.
United could easily have notched several more goals last week had it not been for the heroics of Manuel Neuer who Ferguson said had produced "arguably the finest goalkeeping display against us in Europe in my time".
Asked how important Neuer, who has caught United's eye as they seek to replaceme the retiring Edwin Van der Sar, would be on Wednesday, Rangnick grinned: "I hope a lot less important than last week."
