Graeme Souness says Manchester United must harry and hassle Barcelona's midfield to avoid a second UEFA Champions League final defeat in three years to the La Liga champions.
Sky Sports pundit Souness, a three-time European Cup winner, believes Saturday's Wembley's clash could turn out to be the greatest game ever held in England.
But he says Sir Alex Ferguson's side must not give Barcelona time on the ball and that United midfielder Darren Fletcher must play if he has fully recovered from illness.
"This Barcelona team is the best team I've ever seen play football," said Souness. "They've changed the art of pressing. I've never seen another team press in the manner which they do. It is crucial to the way they play.
"The best team previous to this would have been the Milan team of [Franco] Baresi, all those years ago with Marco van Basten, Ruud Gullit, Frank Rijkaard.
"They would have the ball, lose the ball, drop off to the halfway line and then go for it there. This team can be in your box, lose it and then they press you there.
"They have a fantastic work ethic and it's a very brave way to play. If you can withstand that initial wave of pressing, Barcelona are all over the place because they've committed that many people forward trying to win the ball back immediately that it makes them vulnerable."
Fletcher, 27, returned to United's starting XI on the final day of the Premier League season against Blackpool after seven weeks on the sidelines due to a virus.
The midfielder has already missed the chance to play two Champions League finals in his career - sitting out the 2008 victory over Chelsea as an unused substitute before playing no part in the following year's defeat to Barcelona due to suspension.
Now Fletcher faces stiff competition for a starting spot from Michael Carrick but Souness has a sneaky suspicion that Ferguson will name his fellow Scot in his first-choice XI for Saturday's game.
"Fletcher was the first name in midfield in the first half of the season," said Souness. "It is critical, apart from the system that you play, that you work Barcelona's midfield.
"As hard as you work against them, they will have more of the ball than you but you can't allow them time and time again to get their head up and make cute and clever passes; that's what makes them so dangerous.
"They are all capable of taking it in such tight areas and you've never seen a team that passes the ball to each other when they are being marked by someone and still keep the ball.
"You've got to have a really disciplined midfield; Carrick is a better passer of the ball than Fletcher but if Fletcher's fit for this game I would go with him.
"Ferguson's going to go with Ji-Sung Park and Valencia, so he's already sacrificed a bit of flair for downright, hard-working midfield players and Fletcher certainly falls into that category."
Souness, who will be in the Sky Sports studio with Gary Neville, Jamie Redknapp and Eidur Gudjohnsen for Saturday's game, added: "Everyone's come up with a plan to beat this team; there isn't a plan to beat this team. It doesn't matter what you do to them, the great players come up with an answer to get out of that.
"But by no means is this a formality. Man Utd are a team that, without being the most exciting, is pragmatic and gets the job done."
United proved as much by sealing a record-breaking 19th league title earlier this month, winning the Premier League by a nine-point margin from nearest challengers Chelsea.
Souness says that success coupled to the experience within their squad - particularly in the backline - will ensure that they won't find tackling Barcelona daunting.
"If you are a big player this is what turns you on and you have to be a big player to play at the big clubs," he said. This occasion won't frighten anyone.
"I'm an enormous fan of Nemanja Vidic - he and Rio Ferdinand have a perfect partnership. Vidic is the one who wants to go with everyone, while Ferdinand wants to use his brain and his passing ability and sweep up behind.
"I don't think Barcelona are particularly strong in the air - they are trying to get Eric Abidal into the team for that reason alone - and Vidic is a real threat because he puts his head where a lot of people don't put their feet."
Souness believes Javier Hernandez's movement will also cause Barcelona's backline difficulty, not least because the Mexican striker's positional play brings the best out of Wayne Rooney.
"Wayne Rooney has had a great second-half to the season and I think a large part of that is down to Hernandez," he reflected.
"Hernandez, unlike Dimitar Berbatov, doesn't want to come to the ball all of the time or be involved in the link up stuff - he just wants to get on the shoulder all of the time and he could cause Barcelona a problem. He makes the pitch bigger for Rooney."
Neither can match Messi for sheer ability, though, says Souness.
"I think Barcelona are the best club side ever and in Messi they've got the best player in the world ever," he said. "Nothing seems to bother him; there is absolutely nothing about him to dislike on the football pitch.
"Look at his ability and his attitude when he's just scored a goal or people are kicking him; he has a great personality to be a top player.
"For me he's the best who has ever played and I've played against Diego Maradona and Michel Platini; OK, I didn't play against Pele or Johan Cruyff but he's up there.
"Factor in the modern game and the fact that everyone is quicker than they were in those days and far more aware of what everyone else is doing because of the likes of Sky."
Graeme Souness will be in the Sky Sports studio for High Definition and 3D coverage of the UEFA Champions League Final, starting at 6pm, on Sky Sports HD1.
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