The pals only realised when they were on a minibus to Piccadilly train station that they had actually got tickets for the Blues v Sunderland Premier League clash on February 12 rather than for Sunday's Capital One Cup final.
They went down to London anyway and four managed to buy tickets for the sell-out clash at face-value from kindhearted fellow City fans.
But two, including the lad who made the error, had to watch Vincent Kompany's men land the trophy from a curry house.
Andrew Heald: "A lad called Phil Brierley had looked after it all.
"He'd bought the tickets on the City website ages ago and put them all into envelopes for everyone.
"They hired a minibus to take them to Piccadilly and he handed them their envelopes.
"They opened them and one of them spotted that there was no picture of the cup on their ticket.
"He thought that was odd and looked a bit closer at the date. They saw that they were for the home match at the Etihad that got called off last month!
"They had all paid £70 for a train ticket so they decided to come down anyway and called me to see if I could get them any. I spoke to a tout but he was after £200.
"Fortunately four of them managed to get one from City fans who wouldn't charge them more than face value but Phil and another lad ended up watching it in a curry house.
"He was very apologetic and buying everyone drinks.
"He said he was in a rush when he got the tickets and didn't check properly."