Lionel Messi will be more motivated than usual at Stamford Bridge tonight and that has to be a big worry for Chelsea. It has been well documented ahead of the first leg that Messi has never scored against Chelsea in the Champions League — a run that has so far totalled eight games.

The last thing you want to do is give Messi a bit of a challenge for him to overcome and he will have the bit between his teeth to get off the mark.

For me, the Argentina international is the greatest player of all time and Chelsea will have to pay special attention to him.

Messi is still as good as ever. He is 30 and I don’t see any downturn. The only issue for a player like Messi is when you set such incredibly high standards, a quiet spell leads to people starting to write you off — he hasn’t scored for the past five games so people make more of it.

I don’t think his powers are waning — and the amount of experience he gets from playing at the highest level grows every year.

In a team of great players, he always stands out.

He will be the biggest threat, which just shows how powerful he is. You have to have an element of luck to prevent Messi from scoring. There were times in games I played for Chelsea where we had a bit of fortune.

The thing we worked on to negate Messi was trying to deny him space as much as possible and we did it really well.

We got physical — especially at home. It is something you have to do against Barcelona. You have to be strong and not let them settle into their game. Messi is so good that if you give him space and time, he will destroy you.

I can’t see Chelsea man-marking him because he can pull you all over the place and ruin your own game plan.

I don’t think Chelsea coach Antonio Conte will do that anyway.

I think he will organise the team more specifically so that it is down to the individual to take care of Messi whenever he runs into their area of the pitch.

Whoever is nearest to him has to take the responsibility to take that space because the minute you let him get his head up and run freely at you, you won’t get near him. I can say that from experience.

There will be periods when you just have to back off. The problem is that being at home, there will be people wanting to see Chelsea have a bit of a go at them.

But their players are that good, you have to back off to deny them the space where they can really hurt you.

It is a fine line for Chelsea. They need to sit back but at the same time put pressure on him so he doesn’t become relaxed on the ball.

This is where I think N’Golo Kante will be key. He is the one in Chelsea’s midfield with the abilities you need because he is so quick into the tackle.

But it is important all 11 press their opponents, starting with those players at the top of the pitch.

Conte has a lot of decisions to make about who he plays next to Kante in midfield as well as those further forward.

Out of the two strikers, I would go with Alvaro Morata over Olivier Giroud because he has the pace to run in behind. However, I wouldn’t be surprised if Conte considers using Willian and Pedro alongside Hazard because they combine well, have the energy to track back and cause a threat on the counter.

Chelsea also need to capitalise on Barcelona’s possible weakness in the air. They aren’t used to defending crosses as much in La Liga so they need to take advantage of any set-piece they can get. Barcelona will be in confident mood. They have gone unbeaten in La Liga this term and boast a very good defensive record.

But I’m not sure Barcelona are quite as fluent now as they were in previous years.

The side that dismantled Manchester United in the final at Wembley in 2011 was the greatest team in club football that I have ever seen.

In my era, you had the likes of Andres Iniesta and Xavi at their pomp, alongside Messi, plus talent such as David Villa.

There is a slight element of an end of a cycle and the start of a new one with the current group.

Chelsea do have a chance. Something special tends to happen when these two clubs play together.

During my time we faced each other a lot and that brought an extra dimension to the fixtures.

It is always a huge challenge to face them but we managed to come out on top of them more often. Not many clubs could say that.

Chelsea have always found a way to make it difficult for them and it is just a question whether the current team can do the same.

Barcelona’s players may have the club’s record against Chelsea on their minds even though they will be aware it’s a different side now. I imagine they didn’t want to get them in the draw.

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