But the striker insists the Blues have every chance of going all the way to Wembley if they get past their perennial Barclays Premier League title rivals.
The teams which have dominated English football for the past six years will meet over two legs - starting next week at Stamford Bridge - in a repeat of the 2008 final.
Too close to call: Torres believes his Chelsea team-mates face a difficult challenge in Europe against Manchester United
Asked about Chelsea's chances of ending their long wait for Champions League glory, Torres told Spanish newspaper AS: 'I think it depends on whether or not we get past Manchester United in the quarter-finals, which is 50-50.'
Should Chelsea reach the final, former Atletico Madrid star Torres could come up against Barcelona or Real Madrid, a prospect he would relish.
'I would love to play in the European Cup final, with Chelsea, against a Spanish side,' said the 27-year-old, who backed Real to knock out London rivals Tottenham in their last-eight clash.
'Real Madrid are the favourites to win, although it is not going to be easy,' Torres said.
'That is more 60-40. The Whites are going to have to play really well to beat Tottenham, who have some great players like (Luka) Modric, (Gareth) Bale and (Aaron) Lennon.'
National service: Torres (L) is preparing to take on Lithuania in in Kaunas with world champions Spain
Torres' also reiterated he was not concerned about his failure to score for Chelsea since his record-breaking ?50million move from Liverpool.
Asked if being the most expensive signing in the Premier League meant more pressure for him, he said. "No, not at all. For me, it has been a massive test of confidence.
'The fact that (Chelsea owner, Roman) Abramovich has paid that much money demonstrates that he wants the best team possible - he has ambition and he is not going to give in until he has won the Champions League, which is his dream.'
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