Town drew 0-0 against City at the John Smith’s Stadium in the fifth round of the Cup, earning a replay at the Etihad next week.
However, third-placed Town tackle fourth-placed Reading with chance to put even more pressure on the top two.
Van La Parra said: “For us this is a really important game, and I think that is why the manager made a lot of changes.
“We treat every game the same that we are playing in, but if you look at the Championship table then Tuesday is a bigger game for us and more important.”
On the game against City, van La Parra believes Town deserved a replay just for the manner of the performance the team put in against the Premier League giants.
He said: “We were playing against one of the biggest teams in English football and got a great result against them.
“I think we played really well and we earned a replay. It will give us great confidence that we can hold them to a 0-0 draw.
“You know if you are coming up against Man City, you are coming up against some quality players.
“You have to step up your game and one bad touch is all it takes for them to intercept the ball and create a chance from nothing.
“It is like the manager always says to us, it doesn’t matter who we play, or what the weather is like or what condition the pitch is in.
“All that matters is we do the same things we have been doing.
“Everyone can see that it works and it works against the big teams like Man City too.
“We had some chances in that game, but they also created chances and made it difficult for us.
“When we play them away it will be a much tougher game, and everyone will need to be on their game again.”
With Town’s gruelling fixture list continuing in a Saturday, Tuesday turnaround, it may mean injuries, and possible suspensions, could affect selection.
However, van La Parra is not worried about the tough schedule and says Town’s head coach David Wagner is doing the right thing by rotating the squad.
“It is good to see that when he makes changes, it doesn’t effect the team and we are still as strong as we were before,” he commented.
“I think it is good that we have a big, quality squad. That means the manager can make those changes when needed to freshen the squad up.”