The 28-year-old says the Cats were "a long way off our best" against the Western Bulldogs on Friday night, despite winning the preliminary final by 29 points.
"We conceded a lot of marks, which is something we don't usually do, so we've got a lot of work to do," Mooney said on Saturday morning at Port Melbourne.
"But we know where we're at so we'll be right."
He said the side suffered from having a week off, and was relieved to have made it into a second successive Grand Final.
"It's been two years in a row now that we've scraped through, but at the end of the day, as long as we get through, that's the main thing," he said.
"It's always hard coming off a weekend off. Everyone says it's the advantage but sometimes it's not.
"You lose your momentum a little bit and you come out and you get tired really quickly because you missed the weekend before.
"The weekend off was just maybe not the ideal preparation. We've got through now and it's a whole new week so it will be great.
"We were just happy to get through and off to another Grand Final."
Mooney said the feeling among the players is little different to that of 12 months ago.
"The only difference probably is we've been there and done it, and we know what to expect," he said, of the impending Grand Final festivities.
"Last year there was a lot of pressure on us to break that hoodoo, and this year we're going in more relaxed, I'd say, knowing what's coming and probably just enjoying the week."
He was quick to quash any suggestion the Cats would have an advantage next weekend, having played in a Grand Final so recently as well as enjoying an extra day off between this week's match and the next.
"It might be an advantage but last year, we hadn't been into a Grand Final before and Port Adelaide had been there a few years earlier," he said.
"I don't think that really matters. On the day, if you play good footy, anything can happen.
"I don't think [the time difference] matters. I'm sure St Kilda and Hawthorn would have loved to have played today to get that extra rest, but at the end of the day, recovery is so good with clubs now that I'm sure it won't really matter."
