The seven-time winners were unceremoniously dumped out of the competition in the fourth round at Boundary Park last January, losing 3-2 to the League One side.
It was a different story the previous January when Oldham were on the receiving end of a 5-1 FA Cup thrashing at Anfield and Liverpool have home advantage when the two teams met for a third season running in the tournament on Sunday.
And goalkeeper Mignolet, who joined from Sunderland in June, is keen to secure a safe passage in the draw for round four this weekend.
"For them it is already a cup final," Mignolet told the Liverpool Echo.
"It is already a big game for them to look forward to and they will come here and try to show everyone what they can do at a ground like Anfield.
"We have to make sure we are professional and do a job."
The Belgium international added: "We want to win any game.
"That doesn't make any difference whether it is the FA Cup, Capital One Cup or any other games - we try to step on and prepare ourselves and make sure we get out of the game what we can get out of it.
"I would always watch the FA Cup finals growing up in Belgium. It is a very important competition.
"It is a big opportunity as you can play at Wembley but that is far ahead of us.
"The next game is the most important one and before you get to that stage you have to win a lot of games and against Oldham it won't be an easy game."
