"We still believe we can win the title and it will be like that until the season finishes," the Denmark striker told arsenal.com. "We owe that to ourselves and we want to win it for everyone.
"We are very young but we can still prove people wrong. We shouldn't be written off yet. We're very strong and we have played well against big teams this season. It will be no different on Saturday.
"Yes it's an important game and Man United are a big team but we'll go out there and try to win it like we always do.
"Every match we play against them is big and we believe we can beat anyone with the players we have available."