It turned into a night of capitulation and humiliation for Liverpool.
Anfield is famed for its glorious European nights and yet this one turned into a nightmare for Jurgen Klopp and his players as Real Madrid tore them apart.
It will live long in the memory but for all the wrong reasons and this sort of defeat will surely signal the end for this Liverpool generation.
Incredibly, Liverpool went 2-0 up, and Mohamed Salah became the club's highest-ever European goalscorer - overtaking Steven Gerrard - with 42 goals and yet such records mean nothing after this.
Even with a two-goal head start, Liverpool could not live with Real Madrid and, quite frankly, if they had played for a bit longer the score might have reached double figures.
Liverpool had never conceded four goals in a European tie at Anfield before, let alone five, and yet they produced a crazy, reckless performance which encapsulated all of this season's problems into one night.
They were horribly exposed in defence, Joe Gomez endured an absolute nightmare, keeper Alisson Becker made a catastrophic mistake and they were ripped apart by Real Madrid superstar Vinicius Junior.
Liverpool have enjoyed an incredible ride under Klopp but the German will know better than anyone that this team needs ripping up and rebuilding. They had flair in attack but weaknesses in midfield and defence.
It was just nine months ago that Liverpool lost to Real Madrid in the Champions League final, they were among Europe's elite and yet now they look further away than ever.
It has been a wretched, bruising and damaging season for Liverpool and, even though the second leg is to come in the Bernabeu next month, the last chance of silverware has now all but gone.
They are still hoping to squeeze into the top four but they looked a long way from Champions League quality at Anfield.
Quite how one team has fallen apart so quickly is anyone's guess. Especially as they flew into a 2-0 lead and Anfield was soon dreaming of another special European night.
Liverpool took just four minutes to go ahead. Salah's ball into the box saw Darwin Nunez dart across the back of Eder Militao and the Uruguayan did the most audacious back-heel to put the ball past Thibaut Courtois.
Ten minutes later, Courtois - who made so many big saves in last year's final - miss-controlled a back pass, and Salah nipped in and scored a tap-in from close range. Of all his record-breaking tally, this was probably the easiest.
But it fell apart just as quickly. Vinicius Junior hauled Real Madrid back into the game. He cut inside the penalty box and then fired a shot between Gomez and Fabinho and the ball flew into the far corner.
Madrid were level after 36 minutes. Gomez dropped a back pass just short, Vinicius Junior closed down Alisson and the Liverpool keeper's clearance rebounded off the Brazil star and into the net.
It got worse after half-time. Luka Modric drove a free kick into the box, and Liverpool's defence stood and watched as Militao then ran in to head home.
Karim Benzema then got in on the act. After 57 minutes, Benzema played a one-two with Rodrygo and then the Real Madrid No9’s shot deflected off Gomez and into the net.
There was more to follow. Real Madrid broke again, Vinicius Junior set up Benzema who steered a shot into the top corner. It was five after 67 minutes.
Liverpool's fans chanted: "You'll Never Walk Alone" when the final whistle blew to end their misery. But the truth is that Klopp has probably never felt quite so alone.
