Barca who were without their talisman Robert Lewandowski were in the front seat in the early stages of the match.
Atletico gave several balls away in a dangerous position but Barca could not convert the chances including a one-on-one situation for Pedri who went for the lob but blocked by Rojiblancos' defender.
A quick movement by Pedri opened up Atletico and Gavi with a bold move muscled Reinildo to the ball and dropped it off for Dembele who struck it into the bottom corner to beat Jan Oblak.
The game stood at 1-0 till the end of the match with substitute Ferran Torres and Savic sent off by the referee for a violent tussle.
The victory means Barca have regained a 3 points lead over Real Madrid who slipped to a 2-1 loss to Villarreal.
+3 and +3! pic.twitter.com/C7dpUTHDZ1— FC Barcelona (@FCBarcelona) January 8, 2023