The Argentina international was relieved to see his team bag the full three points against Celtic in the end, and feels they fully deserved their win
The Catalans created numerous chances against the Scottish champions, who had gone ahead thanks to a Georgios Samaras strike, but the hosts were unable to seal victory until the 94th minute.
"I think justice was served, we had 11 or 12 shots on goal to only one of theirs. Justice was served," Mascherano was quoted as saying on the club's official website.
"The team doesn't get tired of pushing forward, we could have given up but we kept on trying up until the end.
"This season is teaching us that a match isn't over until the final whistle, this is not the first time that this has happened to us.
"We had no problems in defence, they didn't create any chances. I think we put in a good performance."
Barcelona sit atop of the table in Group G with nine points from three games.