Mourinho has brought Real to England knowing they must score to stand any chance of preserving their Champions League place.
"Tonight the world will stop for this tie," said Mourinho.
"United are on a fantastic run, better than ever this season. FA Cup quarter-final, winning the Premier League in March, don't lose a match in months.
"But we are also in good form. We have lost one match. It doesn't look a tie, it looks a final.
"Let's see which teams are at Wembley [in the final] but I doubt the expectation can be bigger."
On the down side for Real, Mourinho confirmed keeper Iker Casillas will not make the game.
Although the Spain internationalist has travelled with the squad, he only returned to training on Thursday having sustained a broken hand in January and he will not be considered.
"Everyone is fit and ready to play and be considered, with the exception of Iker Casillas," said Mourinho.
About Cristiano Ronaldo, the Real coach said: "I think he is fine, as far as I am aware. I think any accolade he gets is more than deserved."