Manchester United and Barcelona have already celebrated their league titles, but defeat tonight will lead to one of football's biggest clubs ending the season unfulfilled.

Sir Alex Ferguson has won the Champions League trophy twice in the last 10 years and is desperate to cement United's place in the history books by adding a third.

The level of desire is, however, no lower at the Nou Camp where the Catalans are all too aware that Real Madrid still hold sway as Spain's big hitters in Europe.

Ferguson may have just helped his club draw level with Liverpool on 18 league titles but their bitter rivals retain the bragging rights in Europe with five successes to United's three.

Even though the 67-year-old is giving the impression he can go on and on, time is running out for him to bridge the gap and every opportunity must be grasped.

If they come out on top they will become the first team since the Champions League began in the 1992-3 season to win it in successive years.

The old European Cup provides a rich history of teams who had a period of domination and now Ferguson wants to add United's name to the list.

He said: "I cannot explain why it hasn't been done [winning Champions League back-to-back]. In the history of the European Cup it was done regularly.

"Some won it two or three times in a row. There were cycles of teams winning it like Ajax, Bayern Munich and Real Madrid.

"Now we have an opportunity to change that and hopefully we can take it. There have been a lot of unlucky teams in world football but when you look at the pantheon of great teams you need to have won the European Cup to have that tag. Teams like Manchester United and Barcelona have to win the trophy to be regarded in that respect."

That sentiment is certainly still being felt by everyone at Chelsea, who will be doing their utmost not to watch a final which they believe they, rather than their semi-final conquerers Barcelona, should be playing in.

The Londoners' continued misfortune in the tournament is providing Manchester United's players with even more motivation to ensure they don't miss out.

They are all too aware of how fine the margins are at this level of competition, for if John Terry's penalty in the shoot-out of last season's final had been a couple of inches to the left, Ferguson's side might not be going into this game as defending champions.

Defender Rio Ferdinand (left), who has won his battle to recover from a calf injury and will start tonight, doesn't want to experience what Terry went through 12 months ago.

He has never been tempted to raise the subject with his England colleague while on international dut, but the image of Terry lying on the pitch in tears in Moscow still serves as a warning to him.

He said: "To lose any game is a bad feeling. To lose a game in the Premier League, even in training, is a killer. It ruins your day so to lose a game of that magnitude must really hurt.

"The European Cup final is huge and you don't get many opportunities like this, so I'd like to think we won't taste that."