Manchester United came to Camp Nou hoping for a miracle to rival their 1999 Champions League final victory over Bayern Munich.
Then super-sub and now coach Ole Gunnar Solskjaer scored the second of two stoppage time goals to stun the Bavarians and complete an historic treble for the Red Devils.
Twenty years later, trailing 1-0 from the quarter-final first leg, against a Barcelona side unbeaten in their previous 30 Champions League home matches, they needed a similar freak outcome to progress to the semis.
Barcelona have only twice failed to go through after winning the first leg away from home in Europe, in 41 ties.
And perhaps most importantly, they are led by the one man in world football who is capable of making miracles happen – Lionel Messi.
Solskjaer said on the eve of the clash that he believes in sport you get what you deserve. The truth is Barcelona’s inimitable genius deserves far more than the four Champions Leagues he has to his name.
The best player in the world, in the history of football, produced another decisive, debilitating display, ripping Manchester United’s defence apart to score twice in Barcelona’s 3-0 win, 4-0 on aggregate.
Messi ended a freak 12-match run of Champions League quarter-final games, dating back to 2013, without a goal, driving Barcelona into the semi-finals for the first time since they won the tournament in 2015.
Despite that curious drought, throughout that time he has shone while others around him, from the coach to his team-mates, have not delivered, even if he is willing to shoulder his share of the responsibility.
Last season’s quarter-final capitulation at AS Roma – a 3-0 defeat in the Italian capital – which saw Barca spew away their 4-1 first leg victory, plunged the club into a deep depression.
That unmoving gloom weighed heavily on Barcelona, so much so that celebrations of their league and Copa del Rey double felt trite, while mortal enemies Real Madrid swept to a third consecutive Champions League win.
Time heals most wounds and Marc-Andre ter Stegen explained that Barcelona are only thinking about progressing, with Rome standing as a moment in history they can learn from but not ruminate on.
“We don’t want it to happen again and for that we have to take it into account, but we have to look forward,” said the German goalkeeper.
The double was a hugely impressive achievement, but Barcelona are the only European side to win three major competitions in a season twice. Treble-treble winners has a nice ring to it.
Nine points clear in La Liga and with the Copa del Rey final booked against Valencia, Barcelona hearts and minds are preoccupied by one thing only – conquering Europe.
Captain Messi laid the ground work with a rare speech to fans at the start of the season, demanding his team pull the thorn of the past three years out of their side.
The Argentine star was not at his best in the first leg, struggling after a smash in the face from Chris Smalling which left him bloodied and dazed, but his fingerprints were all over Barcelona’s crucial away goal.
Back on home soil the Argentine magician was far more comfortable. Barcelona weren’t, though, at the start.
“Walking to glory,” read a banner hoisted by home fans moments before kick-off.
The team appeared to take it to heart and were shell-shocked in the opening period by a Manchester United side that flew out of the blocks, hitting the crossbar through Marcus Rashford.
Messi’s magical opener out of nothing eased the pressure, with the No 10 capitalising on Ashley Young’s giveaway, nutmegging Fred and then fizzing a perfectly placed effort past David de Gea from the edge of the box.
Messi’s second, under five minutes later, was less stylish, aided by a howler from the Spanish goalkeeper, but he still ripped away into open green space to find room for his low shot.
Barca’s third should have come just before half-time after another heart-stopping Messi run sliced the Premier League side open, but Sergi Roberto’s shot was somehow kept out by De Gea, who knew little about it.
At times it seemed like Messi was deliberately toying with Manchester United. That’s not often how he plays, but after his roughing up at Old Trafford, he wanted to prove a point – and did.
It was another of Messi’s raking balls out to the left that helped create the third for Philippe Coutinho, with Jordi Alba teeing up the Brazilian.
Now that would really be a miracle, if Messi can help bring Coutinho back to life!
You can’t put it past him – and with the Argentine in this untouchable form, Barcelona’s eyes are firmly on the prize which really matters to them this season.