Barcelona suffered an agonising stoppage time defeat as Alexander Sorloth secured a smash-and-grab 2-1 win for Atletico Madrid that puts Diego Simeone's side top of La Liga.
The Blaugrana made their intentions clear right from the off as they harried and hassled their in-form opponents, who had won 11 games in a row in all competitions.
The dominant hosts - who were without the injured Lamine Yamal - deservedly took the lead on the half-hour mark when Pedri determinedly drove towards the box and then slotted past goalkeeper Jan Oblak.
Raphinha was a whisker away from doubling his team's lead when his lobbed effort bounced off the crossbar and then soon after, they were hit with a sucker punch. After offering precious little, Barca failed to clear the ball and Rodrigo De Paul curled home a classy effort into the corner from the edge of the box in the 60th minute.
Atletico then went into lockdown mode and the home team struggled to break them down. Oblak made some excellent stops to deny Raphinha and Pedri, as Flick's team were left frustrated on Saturday night.
And then with virtually the last kick of the game, Sorloth emphatically rounded off a rapid counter-attack to break Barca hearts, secure their first away league win against their rivals since 2006, and leapfrog them into first place in the division.
GOAL rates Barcelona's players from Lluis Companys Olympic Stadium...