The Argentine admits the Catalans have only a small chance of winning the Primera Division, but he says they must play with the same spirit they showed in beating Athletic Bilbao.
The Catalans appeared to be in crisis after a run of three consecutive defeats in all competitions saw them exit the Champions League, slip to third in the Primera Division and then lose the Copa del Rey final to Real Madrid.
However, the Blaugrana kept their Spanish title hopes alive by coming from a goal down against Athletic Bilbao on Sunday night to move back within four points of leaders Atletico Madrid and edge above Real Madrid with just four rounds of the season remaining.
Mascherano freely admits that Tata Martino's men only have an outside chance of finishing top of the pile but says they must not throw in the towel lest their title rivals slip up.
"We played a good game but we are finding it difficult to score," the defender told Canal Plus after a Lionel Messi free kick earned Barca victory at Camp Nou. "Again, we had to come from behind. We have to be as professional as possible. This is the attitude that we have to show. We have to hold onto that little hope.
"What we cannot allow to happen is for one of those ahead of us to slip up and us not be there to take advantage."
While Barca are now second, third-placed Madrid has a game in hand on the club.