Barcelona started fast, with Marcus Rashford testing the goalkeeper twice inside four minutes, but Atletico quickly settled into their disciplined shape. Despite Barça dominating possession, Simeone's side remained dangerous on the break, with Julian Alvarez threatening early.

The game turned just before half-time when Pau Cubarsi was sent off for a last-man foul. From the resulting free-kick, Alvarez curled in a superb effort to give Atletico the lead.

Speaking after the match, Diego Simeone praised his team's discipline. "Through disciplined collective work, we managed to hurt the opponent at pivotal moments," he said. "The second goal gave us more security."

Despite going down to ten men, Barcelona responded bravely after the break. Rashford struck the crossbar with a powerful free-kick, while Dani Olmo came close at the far post. However, Atletico remained organised and absorbed the pressure.

The decisive second goal came on the counter, with substitute Alexander Sorloth calmly finishing to double the advantage.

Simeone admitted his side chose caution late on. "We preferred to secure the two-nil rather than risk going for a third," he explained. "We know how difficult the second leg will be."

Barcelona boss Hansi Flick was left frustrated, particularly with a controversial handball incident that was not reviewed by VAR. "For me it's a clear red card," he said. "I don't understand why they didn't ask the referee to look at it."

Defender Ronald Araujo agreed, calling the decision "absurd but a clear penalty."

Simeone, however, defended the officials. "There is only common sense about the play," he said, backing the referee's judgement.

The result ended Barcelona's ten-game unbeaten run and gave Atletico their first win at Camp Nou since 2006. Simeone's men now take a strong advantage into the second leg, but both managers expect another intense battle for a place in the semi-finals.

Barcelona refuse to 'give up' as Hansi Flick backs second-leg fightback