There is now a long list of occasions since Unai Emery took charge of Aston Villa four years ago which might have had fans tapping the side of their head. Are we sure we're actually awake, folks? Are we all in the same dream?

This week will probably go to the top of that list - above the Jhon Duran blast against Bayern Munich, above April in Paris, even above the Istanbul trophy lift.

For Villans, apart from fans who remember 1982 for themselves and not as a passed-down memory - and therefore the Super Cup matches the following January - the Nou Camp has been a stadium tour on holiday or the focus of a stag weekend. Somewhere other people go, and otherworldly players play. It could never be you. But now it is.

He would never put it this way, or maybe even think of it this way, but one of Emery's most appealing characteristics is that no supporter is quite as enthusiastic a football tourist as the manager himself.

He has been to all these places before, of course. But he still often carries an air of wonderment when he turns up for his obligatory Uefa news conference the night before the game. (This was most evident in Amsterdam, when he wandered into an auditorium decorated by pictures of Johan Cruyff, head turning like an owl, and explained he had somehow never taken a team here before. "And... it's Ajax!" Suddenly, he was just like us.)

His primary task this week, however, may be to persuade his players not to feel like that. Perhaps this gets a little easier with each passing year as Villa replenish their squad with players familiar with even this exalted level.

A penny, though, for the thoughts of Alysson, of George Hemmings, of the other teenage members of the Villa playing staff on the trip.

Mind you, even though they have experienced the big time for a while, for older hands who served in the Championship mines with Villa and others - John McGinn, Matty Cash, Tyrone Mings - a Champions League night at the Nou Camp is the biggest time.

Barcelona, spraying goals everywhere this season, are as elite as opposition gets. Breathe deeply. Don't look up.

Actually, for now anyway, look at the table instead: Barcelona six points, Villa nine. Never mind who they have played so far, keep your caveats to yourself.

Until Tuesday night, at least, let others do the looking up.