A combustible atmosphere surrounded the Copa del Rey semifinal second leg between Barcelona and Atletico Madrid, with reports that ultras smashed a window on the visiting team's bus during its arrival at the Nou Camp. With Barcelona attempting to overturn a daunting four-goal deficit after a 4-0 defeat at the Metropolitano, riot police were deployed in force to manage the buildup.

Footage circulating on social media showed the volatile environment intensifying moments before the Atletico bus arrived.

Supporters lined the streets in large numbers, waving red flares and chanting as baton-wielding officers monitored the scene. In one clip, a police officer had to kick away a flare that had landed in the road.

Marca understands a group described as "local hooligans" began launching missiles toward the vehicle carrying Diego Simeone and his squad.

One object hit its target and ended up breaking the window of the team's official team bus.

The chaos unfolded amid claims that Diego Simeone and his players were made an "easy target" after entering through a separate gate from the Barcelona team, where the bulk of Catalan police were stationed.

In contrast, the home side's arrival was greeted by fireworks and coordinated chants of "Yes we can! Yes we can!" - a rallying cry reflecting the scale of the comeback required.

Before the match, Barcelona staged a pyrotechnic display inside the stadium to energize supporters for what would have to be a historic turnaround.

At half-time, the Catalan giants were 2-0 up on the night through Marc Bernal and a Raphinha penalty, offering a glimmer of hope in what remained a steep aggregate climb.

Flick calls for belief amid hostile backdrop

Ahead of kickoff, Hansi Flick addressed the scale of the challenge facing Barcelona. "We are four goals behind and we have to make the impossible possible," he said during Monday's press conference.

"That is the objective. It's not easy. However, we will not give up. It is important to keep a clean sheet, but we must believe in our strength and that we can achieve it.

"You must always believe. For example, in each half we need to score two goals."

The German boss also emphasized the importance of unity between players and supporters. "I'm sure the fans will give us their support," Flick added.

"For me, it's important that everyone who wants to cheer can do so. We have to establish a perfect connection between the team and the supporters. When people come to the stadium and support us, I love it."

Barca fans' behavior under scrutiny

The volatile scenes outside the Nou Camp underline the intensity of the rivalry between Barcelona and Atletico, particularly with a place in the Copa del Rey final at stake.

Notably, this is not the first time controversy has surrounded fan behavior in Barcelona.

In 2024, supporters mistakenly threw objects at their own team bus ahead of a Champions League quarter-final second leg, directing missiles while chanting "F*** PSG."

Tuesday's incident will likely prompt scrutiny from Spanish authorities and competition organizers.

While the focus inside the stadium centered on Barcelona's pursuit of an improbable comeback, the disorder outside served as a stark reminder of how quickly football passion can spill into dangerous territory.