Home fires may burn brightly for Ferguson’s side, casting a warm glow on a 12-point lead in the Premier League, but this is Europe, this is a class apart, a challenge to be confronted. This is a game that defines seasons.
On a night of many stars, there is so much to be proved.
Can David De Gea answer his critics, indicate he fulfils Manchester United’s demanding requirements, and show he is the next Iker Casillas? Can Wayne Rooney change contemptuous, and unfounded, local views of him? Can Robin van Persie rise to the occasion in a land where he was sent off on his last visit (with Arsenal at Barcelona in 2011)? Can Cristiano Ronaldo punish those he once cherished? And can Mourinho turn the tide of opinion back his way?
Even Ferguson strode into town with questions to deal with. Even at 71, and emboldened by the experience of 188 Champions League games, Ferguson must demonstrate he can deal tactically with Mourinho, a serial nemesis who has lost only twice to him in 14 meetings.
For regular observers of Ferguson, and particularly those who note how he goes through the motions when discussing Premier League games, it was impossible to ignore the excited look in his eyes at the prospect of taking on Mourinho, Ronaldo and the Bernabéu. This is the acid test for him as a manager. Ferguson arrived in Madrid on a mission.