The Catalans are on the verge of grabbing the Liga title from their bitter rivals, who saw their 18-match unbeaten run shatter at Santiago Bernabeu.
Barca boss Guardiola can't be any happier as he closes in on his first ever trophy as coach.
"We have taken a giant step towards the title and are so close now," said Guardiola after the game.
"We didn't want to hide here and tried to be brave like we have been all season and go for the win.
"It is not easy to win at the Bernabeu and this is one of the happiest days of my footballing life as we have made a lot of people happy."
Chelsea Clash
Guardiola is relishing the prospect of beating Chelsea in the Champions League semi-final in midweek, following the morale-boosting Clasico victory.
Barca only managed a goalless draw at Nou Camp in the first leg, but Pep sees hope of making the final in Rome.
"This win gives us a lot of confidence for the Chelsea game," he said.
"Rome is so close. We don't feel tired and just have to brave and go for it."