Roma coach Paulo Fonseca says their Europa League clash with Ajax is the biggest of the season.

Roma will defend a 2-1 lead in the second-leg of their Europa League quarterfinal.

"It's the most important game of the season so far. We don't have to think about the game played in Amsterdam," Fonseca said at a press conference.

"We'll need the same attitude of the last two games. It will be a difficult match. Ajax are very strong and will want to win, but the lads know how important this moment is.

"We need a perfect game tomorrow. Ajax are a strong team, and we have prepared the game focusing on defensive details. We must defend well as they are solid up front.

"We all know we can't make mistakes. We must be balanced and focused."