McManaman inspired Wigan to last season's shock Cup final win over City.
He can expect to be a marked man when the sides meet again tomorrow, but is undaunted about facing opponents who are on target for a domestic treble after winning the Capital One Cup last weekend.
"The final is still like a blur to me," he said. "I just remember the winning goal, that's it. It is a bit mad really.
"But I was flying around the time of the cup final. It didn't matter who I was up against, I just knew every time I got the ball, I was going to do my job. I had that confidence.
"I had come from nowhere to be playing in the FA Cup final in the space of a few months. It still has not sunk in.
"I don't think anybody who played in it for Wigan will truly realise what we achieved until we look back at the end of our careers. And it was such a shock for football.
"But we have got to believe we can win it again. It would be an even bigger achievement to beat them this year. But if we didn't feel we had a chance, there would be no point turning up.
"City are going to want revenge. They will be up for it. But we'll be up for it. We have won our last five in the league and there is a good vibe about the club.
"I have always played better on the big occasions. I seem to thrive on that pressure. Hopefully, I can do the same again against City.
"I got a kick on my ankle against Cardiff in the last round and have been out for a couple of weeks, but I am getting back to fitness now. I have been training and I feel good."
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