Holders Inter's hopes hanging by thread
"I continue to be optimistic, our goals have not changed," said Inter coach Leonardo, adding his team had come to Germany to turn this tie round. "Anything is possible."
Schalke, who have won all three of their games under new coach Ralf Rangnick, are hoping to finish the Italians off with yet another victory.
"We are leading 5-2 at half-time. Now we have to go out and be equally dominant as in Milan. We will play as if it is 0-0," said Rangnick.
Real Madrid are also in an equally buoyant mood and should complete the formality of eliminating Tottenham Hotspur to set up a probable semi-final against arch-rivals Barcelona.
Jose Mourinho's side travel to White Hart Lane brimming with confidence after demolishing 10-man Spurs 4-0 in the first leg last week. Barring the most unlikely of events, Real and Barca will meet each other in European competition for the first time since 2002.