They may be voted the best side in the world by most pandits, but Barcelona boss Pep Guardiola has made it clear that they will have to be on their feet when they face Sir Alex Ferguson's Man United later tonight at Wembley.

Barcelona got the better of the Red Devils by 2-0 when the two teams last met with goals from Eto'o and Messi but Guardiola believes it will take  alot more than that effort to win the game this time around.

His side are strong favourites to win the title but Guardiola believes they must focus on their game as they have a great opponent in Man U who have a lot of experience under Ferguson.

Speaking on Friday, he has stated, "It's very strange to say that and I'm happy to have won, but let's be honest, we have to play much better than in 2009 to win."

"We have to play much quicker. In terms of intensity and a few other things, they weren't quite as good as we would have liked.

"That is something I have told my players repeatedly over the last few days. If the players who played in Rome played like that now we wouldn't win.”

"I am worried about everything about Manchester United. They have fantastic, powerful players and are as good as we are.

"This not yesterday's team. This is an historic team. They have been through everything and we know how they do things. They are one of the complete teams I have seen in all senses. That is why we have to play a great game."

However the Barca boss who has guided them to their second Cl final in three years at helm has faith in his side's ability and the fact that they know some of the weaknesses of the Red Devils could also work to their advantage says the Spanish.