Luis Diaz was Liverpool's gamechanger as the Reds survived a first-half onslaught to reach the Champions League final.
And the Colombian was reduced to tears in the post-match celebrations.
Holding a 2-0 lead from the Anfield first leg, the Reds were stunned by a vibrant performance from Unai Emery's side in the first half in Spain, where the La Liga side shocked their visitors within three minutes when Boulaye Dia fired home amid defensive disarray.
Liverpool simply couldn't get going in the match, and former Arsenal man Francis Coquelin added a second to completely cancel out the first leg lead shortly before half-time.
Jurgen Klopp's response was to send on Diaz at half-time to replace Diogo Jota, and the game turned as the former Porto man linked up with Mohamed Salah and Sadio Mane impressively in attack.
Fabinho drove a shot through home goalkeeper Geronimo Rulli to pull one back, before Diaz nodded home a Trent Alexander-Arnold cross to level matters on the night.
Sadio Mane would later add a third to wrap up a 3-2 victory on the night for the Reds.
Liverpool's players celebrated their victory with a sense of relief after the match, and cameras caught Diaz seemingly tearing up as he reacted to reaching his first Champions League final.
On BT Sport's coverage, presenter Jake Humphrey labelled Diaz's display "a joke", with pundit Peter Crouch adding: "He changed the game, he was fantastic. The moment he came on, he was getting at players. A complete game changer."
Reds full-back Alexander-Arnold reflected on the win, saying: "We never tend to make these Champions League semis easy for ourselves, no matter if we’re home or away, Barca and now here. It’s difficult, very difficult.
"Obviously we came here, they played very well in that first half, we regrouped at half time and grabbed the game by the scruff of the neck and done what we needed to do.
"It was difficult for us first half, we expected it but sometimes you can’t control the game how you want to. They started well, scored early doors which we didn’t want, but we got the game done and booked our ticket to Paris."
On Liverpool's half-time team talk, he added: "We just needed to play how we wanted to play. We didn’t play football in that first half, never picked up any of the first or second balls at all, then they played how they wanted to and we allowed that.
"It was difficult, second half we played how we needed to, controlled the game a lot better and one bad half over the two legs, we can concede that as long as we got the job done and that’s what we did today."
