“We are underdogs, but we can't go into it with that mindset,” he said.
“We have to go into it like we did against Sunderland and Doncaster and hopefully produce another shock and see what happens.
“Against Sunderland and Doncaster we always felt like we could win and I feel like it's the same again.
“I don't think we were ever out-played in those games. We went there and deserved to win.
“We were holding on a bit at Sunderland, but we were good and more than a match for both those sides.
“Obviously this is a step up this time and it's a Championship club who are going well. We know it will be harder than the previous two games.
“But we're at home so hopefully that can count for something and we can get the fans behind us.
“It's been unbelievable all season – the crowd have been behind us regardless of the results and they have always been supportive of us. “They have been loud and, to be fair, that's probably why our home form has been as good as it is at the minute.”
Stags have won 10 of their last 11 games and Maris said: “On the back of our results it is a good time to play them and we have shown we can cause an upset.
“Hopefully we can play our stuff and see what we can do.
“It is just another game, but there is that extra excitement as we know what the third round is and what it could do for this club.
“We will prepare for it like we prepare for all the league games – focus on us and hopefully that will stand us in good stead to get the job done.
“It's more about excitement than nerves for a cup game like this. We've got nothing to lose against a Championship side.
“We will just go out there and do our best – it's worked in the last two rounds so hopefully we can do it again.”
Maris is hoping this can become his best ever season in the FA Cup.
“I have probably got to the third round once before but I don't think I've ever got past it, so from a personal point that would be nice to do and hopefully get a big draw away from home or a big one here,” he said.
“You want to play against the best – it would be a tough day but it would be an enjoyable experience for the players and the fans.”
Maris said the postponement of both games last week was disappointing as the Stags have great momentum at the moment, helped on by their battling win against Hartlepool on Boxing Day.
“Christmas was one of the best ones football-wise,” he said.
“The gaffer said it's always a better Boxing Day if you win, so we enjoyed Christmas after such a good result.
“But we then had more time off than I would probably like to really. I do like the games coming thick and fast over the Christmas period, especially when you're on this run. You want to keep playing.
“So it was a disruption. But hopefully we've rested up some bodies and we're good to go.”
He added: “We are in a good run of form and starting to get players back to full fitness.
“It's helping as we have a big squad to choose from and competition for places now. We are all confident and hopefully we can produce another shock on Saturday.
“We have had our Covid cases and a few players out, but the majority of them are back now and we are looking good on the injury front as well.
“There is an excitement in the dressing room at the moment. That comes with the results – we are all together and happy. That shows on the pitch.
“Even at 2-0 down against Hartlepool we all knew we'd get back into the game at some point.”