Following on from last week’s 3-3 first-leg thriller, a raucous atmosphere at the start of this second leg crescendoed to Inter’s devastating opener.
Sharp as a tack, Federico Dimarco stole the ball off Dani Olmo in midfield and slid through Denzel Dumfries, who rolled it across to Lautaro Martinez for a simple stroke into the empty net.
Henrikh Mkhitaryan then toed a whisker past Wojciech Szczesny’s post at the other end, but the next plot twist to this thriller came just prior to half-time, when VAR retrospectively judged Pau Cubarsi’s sliding challenge on Martnez to be marginally late.
Hakan Calhanoglu dispatched into the bottom-left corner from the resulting penalty, causing the crowd to erupt, along with Hansi Flick’s temper.
Having won from behind in three of their five prior competitive fixtures, Barcelona once again rallied against the odds and found their way back into the tie when Eric Garcia volleyed Gerard Martin’s cross into the top-left corner of the net within 10 minutes of the restart.
With Barcelona now boasting some newfound momentum, Garcia’s subsequent miss mattered not when another curling Martin ball found an unmarked Olmo, who powered in his header to level the tie - now the first Champions League semi-final since 2022 to hit double figures in aggregate goals.
It was all Barcelona from there, and they went close through Yamal before completing a scintillating second-half comeback with just two minutes of normal time to spare.
Raphinha hit a powerful left-footed shot at Sommer, but the rebound came straight back to the Brazilian, who arrowed into the far corner and put his side in front for the first time in the tie.
But just as the visitors had their hearts and minds turning towards the final, Dumfries crossed for Francesco Acerbi to divert the ball into the top corner at the near post and force an extra 30 minutes.
The hosts looked reinvigorated when play got back underway, and put themselves back in front when Mehdi Taremi cushioned Marcus Thuram’s cross into the path of Davide Frattesi, who slotted into the far corner.
Frattesi could have had another, but the Inter defence held firm to close out a remarkable battle that will live long in the memory.
With history repeating itself after their 2010 semi-final win over Barca, Simone Inzaghi will hope that is a sign that they will go on to lift a fourth Champions League when they face either Arsenal or Paris Saint-Germain at the end of May.
Barca’s hopes of a treble dissipate in the process, but a domestic double will surely be theirs if they can overcome Real Madrid for a fourth time this season in just five days' time.
Flashscore Man of the Match: Denzel Dumfries (Inter)