The Gunners face the Ukraine outfit at the Emirates on Tuesday.
“In this group until now you had 12 points at stake – six went to Shakhtar, six went to Arsenal,” said Wenger.
“That means what is at stake is the qualifying and also the top of the group, which is why it is a very important game.
“It is a key game because it gives us an opportunity to basically think we have qualified.
“Shakhtar are on a good winning run, they are dominating their league, they have just won 3-0 at Braga.
“We are on our toes. We know that only a great performance tomorrow will win us the game.”
