Speaking for the last time before what many believe could be a Wembley classic tomorrow night, Guardiola once again rubbished suggestions Barca were already the greatest club side of all time.

But he admitted lifting a third European Cup in six years playing the way they can could lead to his team being looked back upon in the same way as the great Real Madrid side of the 1950s and 60s, the Ajax team of the 70s and the AC Milan side of the 80s.

"If some guys remember this team, the people who are playing right now, for us that will be a huge success," he said.

"If they talk in good terms, saying, 'One time, I saw this team and this team played good', we are glad.

"To think we're the best team ever, it's impossible, it's not true."

He added: "You need time to go by for people to judge you.

"It's like films. It's only with the passage of time that you know what is a great film."

United boss Sir Alex Ferguson earlier suggested tomorrow's final - between two of Europe's most successful clubs of the past decade - could be the best over that same period.

Guardiola said: "We have to show we deserve this credit.

"To be the best final in the last decade, we're going to try.

"When you play in the final and both teams want to win and both teams want to play and attack for the rest of world, I can imagine it'll be a good final."

Barca have been installed as firm favourites against the side they beat comfortably in the final in Rome two years ago.

But Guardiola claimed the Catalans would lose if they merely repeated that performance tomorrow.

"If we play as we did in Rome, this time we won't win," he said.

"We played worse in Rome than we wanted to. We need to play much better than in 2009 and this is the thing I've told my players over the past couple of days."

Guardiola revealed he had already decided upon his starting XI tomorrow, confirming both captain Carles Puyol and fellow defender Eric Abidal were fit if selected.

"There are obviously factors, variables," he added.

"Ferguson said there were four or five different teams he could play.

"That shows how much talent is in that team.

"Strong points, they've got a lot of them. Weak points, they've got a lot of them too."

He added: "I'm worried about everything. Manchester United worries me.

"They have fantastic players, they're powerful, one of the most complete teams I've seen in all senses."

Both sides know each other almost too well, having squared off in the 2008 semi-finals as well as the following year's final.

The one unknown quantity from a Barca point of view will be United sensation Javier Hernandez, who has been arguably the signing of the season.

Guardiola said: "He's a huge surprise, he's amazing.

"He's amazing when arriving in the area. He has incredible movement without the ball. Manchester United have bought an enormous young talent.

"I am convinced that he will be an important player for the next few years at United."

United have arrived at Wembley despite being branded less than vintage but Guardiola was not buying that and insisted their history had helped create a special club.

"From Matt Busby to Sir Alex Ferguson, they've gone through everything, through plane accidents in Munich," he said.

"When you're lucky enough to play against rivals like Manchester, the only thing you can feel is satisfied and very fortunate."

He added: "To be sitting near Sir Alex Ferguson is an honour.

"So we'll try to enjoy it, enjoy the show and compete, play as well as we can."

But any enjoyment would only go so far.

"You have to compete well and you have to suffer a bit to win," Guardiola said.

"We've been having fun but, from this point, on we have to give what we have to offer and not enjoy it."

Guardiola spent almost his entire playing career at Barca and was in the side that won the European Cup for the first time in 1992, at Wembley.

Responding to rumours his long association with the club could end after tomorrow's game, he said: "Today is not the day to talk about that.

"Leaving? We'll leave that for another day."

For now, all Guardiola is focused on is delivering the kind of performance that has captured the world's imagination.

"It's wonderful to pass on that impression," he said.

"I hope we can continue to show the whole world what we're like.

"We have to show the world more than ever.

"We have to give our all."