with the Reds at the Millennium Stadium last February.
The 20-year-old player spent the festive season reliving the agonies of
that day for the first time on video - and it has made him even more determined to help Blues pull off an upset at Anfield.
Johnson said: "My dad got the tape out over Christmas and we all sat down and watched it. It wasn't easy as we were all over Liverpool in extra-time."
He also remains convinced that Blues should have been awarded an extra-time penalty after Stephane Henchoz appeared to bring him down in the area.
"I had to look at that Henchoz challenge again. I must have replayed it six times and I still think it is one of the most blatant penalties you could ever see. I still can't believe it wasn't given 11 months later.
"There are still players at the club who don't want to see that game again. Martin Grainger has never watched it and doesn't want to.
"But seeing it again has given me the confidence that we can go to Anfield and get something. It wasn't to be last February but we see no reason why we can't give it another go - and we certainly won't disgrace ourselves."
Johnson added: "I know we felt we gave them a good game at Cardiff and I remember Gary McAllister having words with me after the penalties and telling me not to let it get me down.
"That was good because it showed they realised just how much we had pushed them.
Something close to that performance at Cardiff could get a result for us."