Sir Alex Ferguson's jubilation about reaching the Champions League final was tarnished by the "tragedy" of Darren Fletcher's red card. Fletcher had been magnificent as Manchester United overwhelmed Arsenal but he will be in Rome on 27 May only as a spectator and his manager admitted it had tainted a bittersweet night.

"He's distraught," said Ferguson after being unable to console the Scotland international in the dressing room. "He's really disappointed and he is entitled to be. He's one of the most honest players in the game and for him to miss the final will be a tragedy."

Fletcher was sent off after what the Italian referee, Roberto Rosetti, deemed to be a professional foul on Cesc Fábregas 75 minutes into United's 3-1 victory. Fletcher had, in fact, touched the ball away from his opponent but Uefa confirmed there was no scope for appeal.

The only hope of the red card being rescinded is if Rosetti contacts Uefa to admit he made a mistake but even that might not be enough to prevent Fletcher's suspension from the Champions League final, the same fate that befell United's Roy Keane and Paul Scholes when they played Bayern Munich in 1999.

Ferguson watched a slow-motion replay of the challenge directly after the game and he was quick to apply pressure to the man who officiated the Euro 2008 final. "You can see the ball move in a different direction and angle from Cesc Fábregas," he said. "I think he [Fletcher] is terribly unlucky and the terrible thing is that we can't appeal. Mr Rosetti is probably one of the best referees in Europe. He may look at it and come to his own view but there's nothing we can do about it."

There was further sympathy from Arsenal's manager, Arsène Wenger, who described the decision as "very harsh", while United's fans pointedly sang Fletcher's name after the final whistle. "It's very disappointing for Darren," said Cristiano Ronaldo, the game's outstanding player. "He deserves to play in the final. He's fantastic, he's a team player – but this is football."

An unused substitute when United beat Chelsea in Moscow last year, Fletcher would almost certainly have played in this season's final. "You can see his performance tonight," said Ferguson. "He's been a key player for us in all of our big games this season. I couldn't tell you whether he would have definitely played in the final but you would have thought that Darren would have figured largely."

Ferguson, however, said he had deliberately not spoken to Rosetti, a Turin-based hospital manager. "Out of respect to the referee, I wouldn't do that. He may look at himself without anyone asking but I don't think we should ask him. He's competent and fair enough to look at it himself, possibly. But apparently you can't appeal and, if that's the case, that's really disappointing."