However, having dreamt all his life of such an occasion, he is in no mood to let the opportunity go begging.
Mannone said: "It's something I want to achieve for my career, something that stays in history. Being there with Sunderland and having a great chance is something I have always dreamed about.
"When you are a kid, you are looking at the games and you are looking at people lifting the cups and it is really emotional, so you want to be there.
"Each one of us always watched the TV and thought, 'I want to be a winner and I want to lift the cup', and I think that's us, really.
"Each one of us will be thinking about lifting that cup and being important in that game. To have this chance - we are only one game away - is something unbelievable."
Sunderland, of course, would not be walking out at Wembley had it not been for Mannone's contribution to a famous semi-final victory over Manchester United.
The sides were looked together at the end of 120 minutes at Old Trafford in the second leg, and it was left to either Mannone or opposite number David de Gea to claim the glory from a penalty shoot-out.
Mannone saw Danny Welbeck miss the target and Darren Fletcher score from the home side's first two spot-kicks, but he then kept out teenager Adnan Januzaj's effort. After Phil Jones skied his attempt, Mannone dived to his right to deny Rafael de Silva and send his thrilled team-mates sprinting from half-way in his direction.
The former Arsenal goalkeeper said: "It was something amazing, you can't describe it in words. These things happen at the moment that they happen and you can't repeat it.
"You can only watch the video and enjoy it, really. It gives you goosebumps. It's something amazing and something you always dream of as a kid, that your team comes to you in that way and you have got 9,000 crazy fans singing your name.
"Then it carries on and you go into the dressing room and you have got the whole team singing your name. It's something you can't predict."
A similar outcome at Wembley would cause an even bigger upset, with City hot favourites to claim the season's first major prize against a team struggling to retain their Barclays Premier League status.
However, Mannone, who started the campaign as understudy to the now-injured Keiren Westwood, is confident the Black Cats have grown under head coach Gus Poyet, and argues Sunday's result is far from a foregone conclusion.
He said: "It could turn out to be an amazing season, especially because of how it started. We had a few problems in the Premier League and we didn't get as many points [as we would have liked] in the first 10 games.
"But slowly after the gaffer came in, we changed our style and we changed our mentality, and now we have a chance to fight for survival.
"Reaching the final is something we couldn't predict and something amazing for everybody at the club."