“90 minutes is a long time in the Santiago Bernabeu,” Real Madrid’s Juanito famously warned in 1985.
Against any other team in the world, Arsenal could be forgiven for demonstrating a little complacency in light of the three-goal cushion they built on a magical night at the Emirates Stadium.
But this is Real Madrid they're up against. Perennial winners of the UEFA Champions League, Los Blancos have made a habit of achieving the impossible, not least at the intimidating Bernabeu.
Not trying to tempt fate, we've looked back on some of Real Madrid's greatest comebacks in the competition.
First leg: Manchester City 4-3 Real Madrid
Second leg: Real Madrid 3-1 Manchester City
Despite Manchester City dominating prolonged spells of the first leg, Real Madrid emerged from the Etihad Stadium only trailing their opponents by one in a scintillating seven-goal thriller.
Pep Guardiola's side were rampant as they raced 2-0 ahead but Los Blancos persistently mustered a response, going 3-1 down before making it 3-2 and fighting back again after Bernardo Silva scored Man City's fourth.
Karim Benzema capped a spectacular match by chipping a Panenka penalty to score Real Madrid's consolation and little did they know at the time how vital that goal would be.
In the second leg, Man City looked set to foil the unnerving Bernabeu crowd when Riyad Mahrez broke the deadlock with 17 minutes remaining.
Possessing a two-goal cushion, the Citizens had one foot in Paris, but Rodrygo had other ideas.
The Brazilian came off the bench and turned home Benzema's cross to convert Real's first shot on target before levelling the tie 90 seconds later with a sublime header into the top corner.
Shell-shocked by what had unfolded, the visitors succumbed to a euphoric home atmosphere and with the game going to extra-time, Benzema delivered the decisive goal as he converted from the penalty spot after being tripped by Ruben Dias.
First leg: Chelsea 1-3 Real Madrid
Second leg: Real Madrid 2-3 Chelsea
Only three weeks prior to Real Madrid's breathtaking comeback against Manchester City had Carlo Ancelotti's men snatched victory from the jaws of defeat against Chelsea.
A Benzema hat-trick in the first leg at Stamford Bridge appeared to have put Real on course for a comfortable progression to the final four as they ran out 3-1 winners, but very few envisaged what would follow at the Bernabeu.
Chelsea commenced a comeback of their own and were 10 minutes from completing the most astonishing triumph in their history after goals from Mason Mount, Antonio Rudiger and Timo Werner put the Blues ahead 4-3 on aggregate.
But even in a contest where they look comprehensively beaten, you cannot rule Real Madrid out.
Rodrygo spared their blushes by restoring parity in the 80th minute before Benzema sealed the great escape in extra-time as he connected with Vinicius Jr's inviting cross.
First leg: Bayern Munich 2-2 Real Madrid
Second leg: Real Madrid 2-1 Bayern Munich
Two titans of European football clashed in the final four of the UEFA Champions League in 2023/24 and there was nothing to split the two sides after a pulsating first leg in Munich.
Goals from Leroy Sane and Harry Kane were cancelled out by two penalties from Vinicius Jr, leaving the tie finely poised for the return leg in the Spanish capital.
Of course, Real Madrid rarely pursue the straightforward route.
An Alphonso Davies strike on 68 minutes had put Bayern Munich in the ascendancy and on course for an all-Bundesliga affair with Borussia Dortmund in the showpiece at Wembley.
Then Joselu arrived.
Introduced with nine minutes of normal time remaining, Joselu was placed to perfection two minutes from time as he mopped up the rebound from Vinicius' shot to level the scoring.
Just three minutes later and Joselu had etched his name into Real Madrid foklore as he steered Rudiger's low cross beyond Manuel Neuer. The veteran striker was initially ruled offside, only for VAR to intervene and confirm Joselu was onside, sending the Bernabeu into raptures.
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