Villa lead the tie 2-1 after the first leg at home, but Emery knows the game is in the balance.
On team news, he stated: "After Sunday, we are adding Douglas Luiz into the squad.
"lex Moreno has a small injury in his calf and he's going to be out. He's not available for tomorrow and maybe it will be two or three weeks."
On how to play the second leg, he added: We have to play two matches; the first leg we won but it's not enough. We knew before the match it would be very difficult and they showed their capacity, their power and that they're very motivated for this competition.
When we are in Europe we have to be focusing and very demanding if we want to get something here. Now is the moment to show our capacity.
Playing against a team like Lille, they are very motivated and they are a very organized team. The result at Villa Park was not enough for us or for them.
We have to enjoy an amazing day, an amazing match being very demanding. We are ready to play and we are aware of the difficulties we are going to face tomorrow."