Despite Serhou Guirassy's hat-trick and Borussia Dortmund's gutsy performance, Barcelona secured their Champions League semi-final ticket — but with dire warning signs for the future.

Hansi Flick's team was anything but comfortable with a huge first-leg lead. Though the scoreline eventually read in their favor, the game exposed defensive weaknesses and tactical issues that might prove expensive in the next stage.

Dortmund's Fast Start Shakes Flick's Barcelona

Barcelona Survive Dortmund Scare to Reach UCL Semis, But Serious Barcelona Survive Dortmund Scare to Reach UCL Semis, But Serious
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Barcelona's 4-0 victory in the first leg seemed to have wrapped up the tie early, but the return leg told a different story. ESPN reported that Dortmund came out of the gates with aggression and purpose, pressing high and forcing Barça into early mistakes.

Karim Adeyemi's speed and creativity unsettled the Spanish side, leading to a ninth-minute penalty after Pascal Gross was brought down by Wojciech Szczesny. Guirassy stepped forward and scored, sending the home crowd into delusions of a comeback.

For the first 20 minutes, Dortmund took charge, scoring five shots on target and dictating an unrelenting pace. Flick's decision to keep midfield maestro Pedri on the bench backfired, as Barcelona struggled to control possession and composure under pressure. The Spanish league leaders were exposed, especially during transitions.

An Own Goal Swings Momentum Barcelona's Way

While Dortmund continued to drive on, they could not take advantage again of their momentum. Maximilian Beier's half-hour header was easily saved, and gradually, Barcelona began to settle. They never appeared completely in command, but they were able to prevent the game from running away.

The momentum shifted in the second half. Barely minutes after Guirassy headed home his second, Ramy Bensebaini accidentally deflected a Fermin López cross into his own goal. The own goal was a decisive blow to Dortmund's chances of mounting a comeback, taking the wind out of their sails just as they seemed ready to really test Barça's mettle.

Guirassy's Hat-Trick Highlights Barça's Defensive Frailty

Guirassy added the finishing touches to his hat trick with 14 minutes left, capitalizing on a clever play from substitute Julien Duranville. Three minutes later, Julian Brandt had the ball in the net once more — but was called offside.

Although the scoreline was tight, Dortmund never quite seemed likely to overturn the aggregate deficit. Nevertheless, they left a lasting impression — and raised some serious red flags for Barcelona.

Dortmund created 18 opportunities in the second leg alone, and 13 in the first leg. That's 31 chances overall against a side who were dreaming of European glory. The statistics highlight an overarching issue for Barça: Flick's high-line defense can be a liability, especially against sides with pace and accuracy.

Can Barcelona's Frontline Make Up for Their Rearguard?

Hansi Flick's signature pressing strategy has worked well for Barcelona, driving them into a 24-game unbeaten streak heading into this match. But it also leaves them vulnerable, especially when pressing triggers do not work or their midfielders are not composed, The Guardian reports.

This weakness has already been exploited this season in matches against Osasuna, Benfica, and Atlético Madrid, all of which resulted in them shipping four goals.

"I had a feeling something like that would happen today because I know the stadium well," Flick said. "Things didn't go too well for us, but Dortmund played very well. The things we played out weren't what we normally do."