Holding a 4-0 lead after a dominant performance in Catalonia, the visitors were made to sweat as Dortmund and Guirassy nearly pulled off a stunning turnaround.

Guirassy put Dortmund in front with a Panenka from the spot with 11 minutes gone and headed them two goals clear early in the second half.

Dortmund sensed a sensation but Barcelona hit back, Fermin Lopez forcing Ramy Bensebaini into an own goal with just over half an hour remaining.

Guirassy reignited Dortmund's belief with a third on the 76th-minute mark and the final stages may have been different had Julian Brandt not been offside before scoring with 11 minutes remaining.

Despite losing their first competitive game in 2025, Barcelona are through to the semis, keeping their dream of a remarkable treble alive, 10 years after last completing the feat by winning the Champions League in Berlin.

Barcelona, considered title favourites, will face either Inter Milan or Bayern Munich in the final four.

Clearly outclassed in the first leg, Dortmund will take inspiration from Tuesday's performance, not least the goalscoring form of Guirassy.

The 29-year-old Guinean, who has spent most of his career bouncing between the first and second divisions in Germany and France, now has 13 Champions League goals this season, more than any other player.

Despite a big first-leg lead, Hansi Flick made good on his pre-match pledge to continue attacking, opting against resting any of his attacking trident of Robert Lewandowski, Lamine Yamal or Raphinha.

With coach Niko Kovac admitting Dortmund needed a "miracle" to reach the semis after the debacle in Catalonia, the hosts' task got a little harder when captain and centre-back Emre Can was ruled out with injury just before the match.

But Dortmund raced out of the blocks, Guirassy and strike partner Maximilian Beier going close inside the opening 10 minutes before Pascal Gross was the victim of a clumsy foul in the box by Wojciech Szczesny.

Guirassy stepped up to the spot and was nerveless, calmly unleashing a Panenka to get the hosts underway.

Dortmund sliced Barcelona open repeatedly without reward until half-time but made it count four minutes into the second-half, Guirassy heading in a Ramy Bensebaini assist from a corner.

With Dortmund's 81,355-strong Westfalenstadion smelling blood, Barcelona's familiar response was to send their attack down the right and the move paid off almost immediately.

After Yamal's cross was half-cleared, Fermin Lopez found himself in the teenager's channel, whipping a pass towards Lewandowski which Bensebaini hit into his own net.

With Barcelona content to control possession as the clock wound down, Guirassy relit the hosts' hopes when he scored his third in the final quarter of an hour, blasting in from close range after some delightful dribbling from teenage winger Julian Duranville.

The home fans erupted when Brandt scored three minutes later, but the midfielder was offside, allowing Barcelona a breather.

Barcelona managed to hold on despite waves of energetic Dortmund attacks in the final stages to remain on track for the treble.