Lionel Messi and Sergiño Dest both netted braces and Ousmane Dembele also scored as Barça kept within four points of Atletico at the top of La Liga.
“Sometimes we struggle to score the first goal but we were really fluid tonight and played really well,” Griezmann told Movistar.
The French forward added that he didn’t celebrate “out of respect for playing” for La Real earlier in his career as he celebrated turning 30 with another goal.
“Sometimes it’s not your day in the final third, sometimes I miss, others times it’s Ousmane or Martin… we work on that, to improve,” he added.
“But here everyone scores goals. We have to be switched on mentally, those that aren’t playing have to be atent, they can make the difference, too. We’re a group and that’s the only way to achieve big things.”
On the title race, Griezmann said Barça aren’t focused on Atletico: “We have to look at ourselves and do all we can to be champions.”
And on the new formation, he said: “What’s best for me is to be on the pitch, that’s what I want, but yes, with three centre-backs we’re more secure, the midfield works a lot… the boss has hit the nail on the head.