The Catalans have lost three of their last four games after a 39-match unbeaten run stretching back six months was ended earlier this month.
However, they remain in control of their fate in La Liga as they would need to drop points in two of their last six games for Atletico Madrid or Real Madrid to snatch the title.
“When you are in a situation like this we are going to need a monumental effort.
“We need to be stronger than ever, we need to help each other, stay together in every area of the pitch and we will need the support of our fans.”
Barca face a Valencia side in search of revenge on Sunday after they were thrashed 7-0 on their last visit to the Camp Nou when Enrique’s men were flying back in February.
However, Enrique is counting on home advantage to carry Barca on a busy week of league action as they also travel to Deportivo la Coruna on Wednesday before hosting Sporting Gijon next Saturday.
“We aren’t in our best moment of the season, but that is part of the course of a season and we have to learn how to accept that against Valencia,” he added.
“We only have eyes for Valencia because that is the closest objective, but in a week we will play three league games, half of what is left.
“Two of those three are at home and I remain optimistic that, even though it is a situation that we don’t like, we can be league champions.
“It won’t be easy, but we never said it would be a walk in the park.”
