Arsenal boss Arsene Wenger admits their clash with Everton will be decisive in the top four battle.
Roberto Martinez's team have won five games in a row in the Premier League and have the chance to go one point behind Arsenal with a victory at Goodison Park.
"It's an opportunity to go forward and as well an opportunity to make a distance with Everton," he said. "As I told you after the last game against Man City, we look in front of us and behind us as well. That's what the game is about on Sunday.
"Everton are a good side, that's why they are where they are. I think in the first game [in December] we were caught just at the end. In the second game we won 4-1 and scored two late goals, so they were two interesting games. I think it will again be very interesting on Sunday.
"For us it's very difficult to imagine the impact it will have on finishing fourth, but it's a game we want to win. Everton have won against Swansea in the last minute and they have a never-give-up attitude, which gives them credit.
"They still have a difficult programme as well - like all of us they have to play a lot of difficult teams."
