Spanish football expert Graham Hunter previews the Champions League game between Celtic and Barcelona. Here’s what Celtic must do to get a result tonight…

There was once a bit of the Dr Bruce Banner about FC Barcelona. Ok, not the green skin and the tendency to overturn cars, but the ‘Don’t make me angry, you wouldn’t like me when I’m angry’ bit was true enough.

Over the last few years when teams had the temerity to catch Barça on a bad day and push them around, or to deny them the joy of skipping around the pitch with the ball by choking their space and thinking time then, sooner or later, there’d be a pay back.

Immediately within that game, next time they met, sometimes over and over again: ‘That’ll teach you.’

But it’s to Celtic’s great advantage that while that spirit is still central to the ‘Cogigo ergo sum’ – I play therefore I am – attitude of this team, the mind is willing but the physique is weak.

You don’t take points off players like Xavi, Iniesta, Valdés or Busquets in the manner Celtic did last season without it rankling.

Revenge? No, that’s not their guiding thought process. But, like big Jack Charlton used to have a little black book of accounts pending, for bruises and late tackles, so the Barça boys still remember where they need to address issues from a previous meeting – just to try to restore their football feng shui. Getting the three points is of supreme importance, but putting things back in order will be in their heads too.

Barca brutes no more

While Barcelona have been the dominant European team over the last seven years it’s natural that a great deal of focus has been on their technical excellence, their attacking flair, their playing system and also on the fact that two of three of these players, Ronaldinho in his day, Xavi, Iniesta and of course Messi, will rank amongst the greatest that any of us can expect to see in our lifetimes.

What sometimes gets pushed aside is the fact that they used to be a brute to play against. Physically very strong, ferocious in their pressing and constantly working at an incredible rate of knots.

That’s not so true any more. The gradually frittering away of players like Yaya Touré, Seydou Keita, Thierry Henry, Edmilson, Rafa Marquez, Samuel Eto’o and the injury damage age is doing to Carles Puyol means this is a more delicate Barça side. In body if not in mind.

TALL ORDER: Gerard Pique (seeing off the challenge of Conor Sammon at the Euros) is raring to go vs Celtic

Tata carries same issues as Tito

This is still an exceptional team. It is still very hungry, it still has a cobra-like ability to pounce on moments of inattention or error.

But even though the new coach, Tata Martino, is an extremely interesting football student, has clear and well articulated ideas and even though he’s showing a very firm hand in rotating the team with absolutely no fear of resting the biggest names, he carries some of the same problems into this match that Tito Vilanova did.

Gerard Piqué is on athletic, hungry form and didn’t play for the large part of the defeat here last year but, around him, Barcelona haven’t added any height to deal with the aerial problems they have at set pieces into the box and the diagonal ball in from open play.

Under Martino the Catalan defence is man-for-man rather than zonal and, perhaps, that will make a difference in due course. At Celtic Park they’ll be tested.

Celtic simply must score first

Another part of Barcelona’s repertoire which was like a pair of steely jaws clamped on your ankle but which is now showing rust is how  they do (or in fact often don’t) close games off once they are leading. Saturday’s 2-0 win at Almeria being an interesting exception.

It’s still absolutely vital for Celtic get the first goal if they want a chance of repeating last year’s excellence. But there was once a time that if Barcelona scored first they almost never released the choke-hold in a game that mattered to them. Not quite so true any more.

The pressing has changed, too. It’s beginning to work under Martino but there is geographical alteration. Under Pep Guardiola, in the golden years, the pressure began on the edge of the opponents’ box. Martino’s idea is that the central maelstrom of pressure on the opponents should be about three-quarter of the way up the pitch with strikers and wing backs pressing vertically, like a pincer, and midfielder moving in horizontally.

Right now, notwithstanding Messi’s absence, Barcelona are sharper, firmer and better prepared for this test than they were 11 months ago. They shape up as single goal winners, I think.

But invulnerable? No, not that.

• Celtic v Barcelona betting: Fancy Barca to win by one goal at 12/5? Crunch into the latest odds here >

Graham Hunter is the author of the award-winning book, Barca: The Making of the Greatest Team in the World. There’s a new book on Spain about to drop. Graham is a regular contributor to the Paddy Power Blog on football and an all-round good guy. Follow him on Twitter here

Dive into Hunter’s archives on the Paddy Power Blog here

Want £200 Free? Click here to visit Bet365 and claim your free money.