Antoine Griezmann had to score. The French midfielder had received the ball at an inviting height three yards from goal, with time enough to pick his spot. But he scuffed his shot, allowing a retreating Ronald Araujo to clear the ball off the line and preserve Barcelona's 1-0 lead.
It was the last act of a tense matchup between Barcelona and Atletico Madrid, with Araujo's heroics proving vital as Xavi's men emerged from the Wanda Metropolitano with all three points.
Barca created relatively few chances, but were ultimately the more clinical of the two sides. Dembele grabbed the only goal, while Araujo and Andreas Christensen put in admirable performances in central defence to keep a surging Atleti side out and establish a three-point lead over arch-rivals Real Madrid at the La Liga summit.
Dembele opened the scoring for Blaugrana in sublime fashion. Pedri picked up the ball in central midfield 22 minutes in and evaded two defenders with a superb show of dribbling ability before feeding Gavi, who then flicked it on to a wide-open Dembele. The French international was celebrating before his first-time shot hit the back of the net as Jan Oblak was left with no change in the Atleti net.
After falling behind, the hosts woke up. Jose Maria Gimenez sent a header wide. Greizmann had a shot tipped around the post. Marcos Llorente struck a volley into the side-netting. But the home side couldn't find an equalizer before half-time. Still, they continued to press forward in the second period and seemed to frustrate a tired Barcelona with their constant pressing. Tempers frayed in stoppage time as Stefan Savic and Ferran Torres were both sent off for a WWE-worthy brawl before Griezmann was eventually presented with the golden chance Atleti craved, but it went begging and the visitors held on for the win.