Liverpool produced one of the greatest comebacks in Champions League history to beat Barcelona 4-0 on Tuesday, overturning a three-goal first-leg deficit and advancing to their second successive final with a 4-3 aggregate victory.
Two goals each from stand-in forward Divock Origi and halftime substitute Georginio Wijnaldum left Lionel Messi and Barcelona utterly shell-shocked by a Liverpool performance full of passion, belief and determination.
Jurgen Klopp's side will play the winner of Wednesday's other semifinal between Ajax Amsterdam and Tottenham Hotspur, with the Dutch side leading 1-0 from the first leg in London.
"Unbelievable. I don't think many people gave us a chance," Liverpool captain Jordan Henderson said.
"Before the game we knew that it would be difficult but it was still possible, of course. It's amazing. We knew that at Anfield we could do something special."
Liverpool become only the third team in the history of the European Cup or Champions League to come from three goals down after the first leg of a semifinal and progress after Panathinaikos in 1970-71 and Barcelona themselves in 1985-86.
For Barca, who went out on away goals to AS Roma in the quarterfinals last year after winning the first leg 4-1, it was a bitter night that will raise many questions for coach Ernesto Valverde.
Messi, whose two goals in the first leg had given his team a seemingly comfortable advantage, was unable to make his influence on the game count with an away goal that would have been decisive.
Liverpool, without two-thirds of their strike force with Mohamed Salah and Roberto Firmino injured, took a seventh-minute lead when a poorly headed clearance from Jordi Alba fell at the feet of Henderson, who burst goalward.
His low shot was parried out by Barca keeper Marc-Andre ter Stegen but straight to Origi, who slotted home.
Barca had openings in the first half, but when Messi twice got space around the box he fired wide of the target, and when Jordi Alba burst goalward just before halftime, Liverpool keeper Alisson Becker was out quickly to nullify the danger.
Two minutes later Wijnaldum rose to meet a Xherdan Shaqiri cross with a powerful header to make it 3-3 on aggregate.
Liverpool then grabbed an extraordinary fourth goal with a quickly taken corner from Alexander-Arnold, catching the Barca defence asleep with a low ball that was turned in at the near post by Origi.
That sent Anfield wild, but then Klopp's side suddenly found themselves needing to switch mindset and defend a lead as Barca slipped, belatedly, into their trademark possession game.
Klopp's side, who lost to Real Madrid in last year's final in Kiev, remain in with a chance of a double triumph as they head into Sunday's final round of Premier League games trailing leaders Manchester City by just a point.