From the very first minutes, Atletico Madrid showed thorough preparation and high determination by pressing Barcelona with a high-pressure style of play.
That pressure quickly paid off in the 7th minute, when goalkeeper Joan Garcia fumbled a back pass from Eric Garcia, allowing the home team to capitalize on the mistake and open the scoring.
The early goal conceded caused Barca to lose confidence, while Atletico became even more energized and pressed forward.
Diego Simeone's team constantly exploited the gaps behind the opponent's high defensive line. Giuliano Simeone, Griezmann, Julian Alvarez, and Lookman combined dynamically, disrupting Barcelona's defensive system.
In the 14th minute, Griezmann calmly doubled the lead. Then, in the 33rd minute, Alvarez provided a perfect assist for Lookman to make it 3-0.
But that wasn't all; before the first half ended, Lookman returned the favor with an assist for Alvarez to score the fourth goal in the 45+2 minute, capping off a disastrous 45 minutes for the visitors.
In the second half, Barcelona tried to fight back, but their goal was disallowed because Lewandowski was offside.
In a deadlock, Lamine Yamal was completely neutralized, and Eric Garcia received a red card in the 85th minute. The 0-4 defeat puts coach Hansi Flick's team in an extremely difficult position ahead of the second leg at Nou Camp.