Speaking for the last time before what many believe could be a Wembley classic tonight, 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 manager Sir Alex Ferguson earlier suggested the 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 2-0 in the final in Rome two years ago. But Guardiola claimed the Catalans would lose if they merely repeated that performance tonight.
“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.”
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.”
The Barcelona coach revealed he had already decided upon his starting XI, 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.”