Ousmane Dembele scored a 90th-minute winner to take the Catalan giants to within just one point of league leaders Atletico Madrid.
Lionel Messi, who was honored by Barcelona before the game (for breaking the all-time appearance record), was overheard in the tunnel motivating the team.
This fixture was absolutely crucial for Barcelona's title hopes, and Lionel Messi's words at half-time showed what it meant to him and the team.
Messi could be heard saying:
"We have to step it up a gear, we have to play with more rhythm. We have to win this however we can"
After starting the season in indifferent form, Barcelona now have the chance to claim an incredible domestic double in Ronald Koeman's first season in charge.
With Lionel Messi all charged up and focused, Barcelona fans will be hopeful of ending the season with silverware.
Lionel Messi's Barcelona future has been subject to intense speculation
Lionel Messi's Barcelona contract will run out at the end of this season, and the Argentine maestro has reportedly still not made a final decision about his future.
The six-time Ballon d'Or winner is back to his magical best in 2021, and it will be interesting to see if he signs a new contract at Barcelona.
Joan Laporta has been very vocal about Lionel Messi's importance to the club. In fact, as soon as Laporta was named Barcelona president, he made an impassioned plea to Lionel Messi in his speech.
Laporta told reporters:
"In our first spell we had the best players in Barca history, but if we were successful it was because we had stability."
"It is Barcelona's unity which gives you stability and I invite everyone at Barcelona to think about what they can do for Barca.
"I am here to make decisions, like convincing Leo to carry on, taking advantage of the fact that he is here. He knows that.
"You know the affection I hold for you and we will do whatever it takes to keep you here. You know you cannot leave, Leo."
With things looking up for Barcelona, Lionel Messi might just end up staying at the Camp Nou beyond this season.