LIVERPOOL, England -- Jurgen Klopp hinted that he didn't believe Liverpool could pull off a Champions League miracle against Barcelona, admitting Monday that "beautiful failure" was perhaps the best his team could hope for against the Spanish champions.

Come on, Jurgen, you need to have more faith. Your players have shown they are capable of anything, but nothing can match this: a 4-0 rout of Barcelona when every odd was stacked against them.

Trailing 3-0 from the semifinal first leg in the Camp Nou, when Liverpool were taken down by the genius of Lionel Messi, Klopp and his players had the faintest of hope going into the second leg at Anfield. To make their task even more daunting, they had to make do without their two world-class forwards -- Mohamed Salah and Roberto Firmino -- due to injury.

But this is Liverpool, and this is Anfield, and, well, all the myths and fairy tales surrounding this place came true on an unforgettable night of pulsating and fearless football. Barcelona -- mighty Barcelona -- were ruthlessly dispatched with two goals from a makeshift striker (Georginio Wijnaldum) and another two from a player (Divock Origi) who was on loan at Wolfsburg at this time last season.

This was Liverpool's night, make no mistake about that. It was a comeback for the ages, topping anything this historic old ground has ever seen, but Barcelona played their part in a way they never could've imagined in their worst nightmares.

They were supposed to have learned their lessons from last season's quarterfinal meltdown in Rome, when a 3-0 defeat saw them crash out in the Stadio Olimpico, but this was worse. Barca collapsed. Perhaps they started the game believing it was won -- too complacent, too arrogant -- and Liverpool punished them mercilessly.

But this is what Liverpool do at Anfield on European nights, regardless of who is in charge on the touchline. From David "Supersub" Fairclough's winner against Saint-Etienne in 1977 to Luis Garcia's "ghost goal" that was enough to beat Chelsea in 2005 to the incredible fightback against Borussia Dortmund in 2016 and the pummeling of Manchester City last season, Anfield turns the men in red into superheroes when European glory is at stake, and Barca became the latest and greatest name on that lengthy list of victims.

Yet the noise from the Kop was only one ingredient of this stunning victory. The supporters were the 12th man, but Klopp and his players were the architects and builders of a win that took Liverpool to next month's final in Madrid.

Alisson, the Liverpool goalkeeper, was part of the Roma team that produced its own miracle against Barcelona last season, and he admitted that that result played a part in his preparation for this tie.

"You try to visualise it before the game, but it's nearly impossible to do, to imagine that things will work out just as you want them to," Alisson told Sky Italia. "It happened for me last year with Roma. It happened again tonight."

To turn this tie around, Liverpool had to get everything right. They could not afford Barcelona any opportunity to score a killer away goal, which would leave the home side needing to score five, and they had to take every big chance that came their way.

-- Social reaction: Liverpool rally to shock Barcelona
-- Barcelona ratings: Alba 3/10 as his mistakes start collapse
-- Liverpool ratings: Origi, Fabinho top list of heroes vs. Barca

But good fortune smiled on Liverpool in the seventh minute, when Jordi Alba's misplaced header fell into the path of Sadio Mane, who fed the onrushing Jordan Henderson. The Liverpool captain burst into the penalty area and shot goalward, but his effort was saved by Marc-Andre ter Stegen. The Barca keeper could only palm the ball away, however, and Origi struck from 6 yards to give Liverpool the dream start.

Anfield shook, but Barcelona responded with fire, as Messi forced Alisson to tip a clipped shot over the bar on 14 minutes. Luis Suarez, once the darling of Anfield, became its enemy as he became embroiled in ugly tangles with Andy Robinson and Fabinho, prompting his old fans to decry him as a "cheat" and then sing "F--- off, Suarez!"

The passion in the stands drove the Liverpool players, but half-time arrived, and it was only 1-0. Liverpool needed two more goals. But Wijnaldum, a half-time replacement for the injured Robertson, earned himself a place in Liverpool folklore by scoring twice in the space of 120 seconds, on 54 and 56 minutes, to haul Klopp's team level on aggregate.

If Anfield shook after Origi's opener, it was now rocking from its foundations because the crowd sensed that Barcelona were falling to their knees. Even Messi looked shell-shocked by the scenes around him.

"Things got on top of us after those two quick goals," Barcelona coach Ernesto Valverde admitted post-match. "We didn't manage to get on the score sheet, and they rolled us over, really."

Valverde was right. Barcelona were rolled over. So much for the best team in Spain; they simply crumbled when faced with Liverpool's intensity and hunger.

But it wasn't all done at 3-0. Barcelona were still in it, knowing one goal would swing the pendulum back in their favour and keep them on course for Madrid. Yet their world well and truly caved in on 79 minutes, when Origi struck again to make it 4-0 and put Liverpool ahead.

Barcelona simply fell asleep at a corner, with Trent Alexander-Arnold's cross to Origi catching them completely flat-footed. Origi still had a job to do by putting the ball into the net, but yes, this is Anfield, so where else was it going to end up?

It was 4-0, and thousands of Liverpudlians could start to book their flights to Madrid, while the same number of Catalans began to cancel their hotels. This was Liverpool's night, and nobody inside Anfield will ever forget it.

"The whole game was too much," Klopp said. "It was overwhelming. We played against maybe the best team in world. Winning is difficult, but winning with a clean sheet, I don't know how they did it. It's unbelievable.

"I saw James Milner crying on the pitch after the game. It means so much to all of us. It's the best phase of football. There are more important things in the world. But creating this emotional atmosphere together is so special."

Beautiful failure? Maybe not. Liverpool's sixth European Cup is waiting to be lifted next month.