No side has ever come back from that deficit to win the title, but Zidane remains confident his team can turn things around and put Ernesto Valverde's high-flying Catalans under pressure.
"We played a great game and deserved more tonight, but it was not to be," Zidane told reporters after the game.
"We should be patient. We are on the right path.
"Barca will surely lose points. We have to continue with our work and that's it."
Cristiano Ronaldo and Karim Benzema's travails in front of goal continued at the Wanda Metrpolitano and the pair have now only scored two goals in 16 combined league appearances this season.
Zidane, however, believes that the goals will start flowing again soon for his beleaguered strikers.
He added: "Sometimes there are times when it [the ball] does not want to go in. I cannot explain it to you.
"The good thing about tonight is that we played very well. But it's true, we are lacking goals.
"It will come. You have to be positive and we are positive."