The Reds, famously, went into the second leg of the tie 3-0 down after defeat at the Camp Nou, but stunned their opponents – and the footballing world – with a 4-0 victory at Anfield, thanks to doubles from Gini Wijnaldum and Origi.
The Belgian became an unlikely hero for Liverpool in the Champions League that season. The forward had been a peripheral at the club but got his chance to lead the line in the semi final amid a slew of injuries, taking his chance with two historic goals.
However, while Origi, Wijnaldum and, of course, corner-taker Trent Alexander-Arnold are frequently credited for their part in perhaps Anfield's greatest European night, the now Nottingham Forest forward drew attention to Jurgen Klopp's part in making his team believe in their chances.
Origi told GOAL of the manager's ability to inspire: "To be honest in terms of speeches before games bro, he’s the best I’ve seen, goosebumps bro... he speaks from the heart bro, it’s crazy. I just remember. I don’t remember exactly what he said (before the Barcelona game) it was a long time ago... he came with the energy. He was like ‘yeah we can do this’.
"We knew it was gonna be hard but we knew if things was gonna align; the fans, first goal early, even the quality we had in the squad and the heart we played with that year... pffft."
Origi's comments align with those of another former Liverpool star from that team Fabinho, who revealed earlier this year how the boss kept spirits up after the first leg loss.
He wrote in an article for the Players' Tribune: "In the changing room after the game, of course we were down, but we still had this optimism. At one point it was just Klopp, [Sadio] Mané and me left in the room.
"We were all saying, 'How did we lose this 3–0?' And then Klopp asks us, 'But do you still believe we can win the second leg and make it to the final?'
"I went first: 'Yes, I think so.' And then Sadio said, 'Yeah, so do I.' And Klopp was like, 'Good. Because I think so too.'
Liverpool went on to beat Tottenham in the final of the 2019 Champions League, with Origi scoring a late clincher to make it 2-0.
Now back in England with Forest, the 28-year-old has played in eight games this season, but is yet to find the net – starting just once.