Emery admits their top four chances now hinge on the game.
Asked if Arsenal now have to win at the Premier League's bottom club, the Spaniard stated: “Yes".
Emery stressed his players need to focus even against a team who have lost 11 of their last 12 Premier League games.
“I spoke with the players [and said]: 'We need to think this match is very important for us and every player needs to be ready, be focused and be thinking we need to win this match." he said. “Imposing ourselves from the first minute, and throughout the 90 minutes, our capacity against them'.
“But first is the mentality. I think we can take better balance when we prepare the matches by thinking it's going to be very difficult.
“For us, tactically, is the second issue. The first is to think we need to win and after it's how we can win this match – preparing tactically and individually."