Villa are yet to record a win this season.
"We have to prepare quick because on Tuesday we have another game and we have to win," said El Ahmadi to the Villa's website. "We have to show some character as a team and as players. We are professionals and we have to stand up.
"Everybody is disappointed about Everton because in the first-half we didn't play good but we didn't need to be 3-0 down. I think in the second half we worked hard and tried to do something, especially with 10 men.
"Everton were good but we can also say to ourselves that we weren't sharp at the beginning. At 3-0 the game is more or less over but we still tried to score some goals in the second half.
"We can be disappointed but we have to go forward and think about the next game."