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Sorloth, a second-half substitute, applied a fine finish past Inaki Pena with 96 minutes on the clock, converting Nahuel Molina's cross to win the game after the visitors had been largely dominated by their hosts.

After peppering Jan Oblak's goal in the early stages at Lluis Companys Olympic Stadium, Barcelona went ahead on the half-hour mark when Pedri started and finished a slick move, beating Oblak at his far post from inside the area.

Barcelona continued to push on, but it was Atletico that had the last chance of the first half, Julian Alvarez unable to poke home Javi Galan's cross from inside the six-yard box.

The chances continued to mount for Barca in the second half, Fermin Lopez forcing Oblak into a save two minutes after the restart.

Raphina came even closer to doubling the lead as he broke clear and chipped the Atletico keeper, but the attempt bounced off the top of the crossbar.

Those missed opportunities would prove costly on the hour when Atletico equalised.

Alvarez broke down the left and delivered a cross that was only half cleared by Marc Casado, falling right into the path of an on-rushing Rodrigo De Paul, who fired home superbly from the edge of the D to level things up.

Barcelona pushed for a winner, but top scorer Robert Lewandowski was guilty of missing two gilt-edged chances before Dani Olmo pushed another effort just wide.

Oblak then produced more excellence as both Raphina and Pedri were denied at close quarters, allowing the possibility of an Atleti counter as the hosts pushed up the field for a winner of its own.

Sure enough that chance came when Raphina misplaced a pass and De Paul broke down the right. Molina made an excellent run to give him an inside option, which he accepted, and the final cross was met by Sorloth first time on his left foot, silencing the home support and sending Simeone sprinting away in delight as his side secured the win and top spot.

Atletico is now three points clear of Barcelona on 41 points and also has a game in hand on Hansi Flick's side, which could end the year in third place should Real Madrid win its last match of 2024 against Sevilla on Monday (AEDT).

Watching on from the stands as he served out his touchline ban, Flick must have wondered what more his team had to do to win the match.

Barca created chances worth 2.5 expected goals, having 19 shots to Atleti's five, but the visitors hit the target with four of those in a clinical show of counter-attacking force.

Flick's previously much-hyped defence has also now become a huge cause for concern.

Barca has now conceded in each of its past eight LaLiga games, its worst run without a clean sheet in the competition since one of 11 between September and November 2018.

It has lost four of its past seven LaLiga matches, recording only one win in those seven, as many defeats as in its previous 34 games in the competition, of which it won 27.

Oblak said after the game that his side must not get carried away after this victory, which could prove key in the race for the title.

"I hadn't won in Barcelona since I arrived [at Atletico], finally. It was difficult, but we got three points. Let's continue in this vein," Oblak said.

"We started badly, with some fear that nobody understands, because we are in very good shape. After the 1-0 we were able to hold on without conceding the second.

"The league is very long. Today is not key, it's three points and there are a lot of points left. A month and a half ago we were far away and now we are here." 

De Paul, who after restoring parity in the match has now scored three goals in his past four LaLiga appearances, also hailed the win.

"When you suffer more, you enjoy it more. We were up against a great rival. It had been many years since Atletico had won here, and we were also playing for the top spot," he said.

"It's exciting to be leaders. It's a huge satisfaction. When your work pays off, you feel completely satisfied. It's an honour to wear this shirt, and when things go well it gives me great joy."