The Reds went into their second leg at Anfield with a 3-1 advantage.
It looked as if they would cruise through to the last four as they led 3-1 on the evening (6-2 on aggregate) with 25 minutes remaining.
But Benfica staged a late comeback.
Quick-fire goals from Roman Yaremchuk and Darwin Nunez reduced the deficit to just two goals with nine minutes remaining.
Benfica had their tails up and Liverpool could have been in more trouble if it weren’t for their brilliant goalkeeper, Alisson Becker.
Alisson has saved Liverpool on countless occasions before and he was at it again on Wednesday.
Just moments after Nunez’s goal, Benfica broke up the pitch and Nunez fired a powerful effort that looked destined for the bottom corner.
But the Brazilian goalkeeper produced a stunning save to deny the 22-year-old. Watch it below…
Benfica forward Darwin Nunez:— Watch LFC (@Watch_LFC) April 13, 2022
"That Alisson save? That was incredible. I swear to you, I saw the ball going in.. and then it wasn't."
It’s one of many tremendous saves Alisson has made since signing for Liverpool in a £72m deal from Roma in 2018.
Nunez put his hands on his head and looked away in disbelief.
Liverpool held on to secure their spot in the final four.
Nunez was still in awe of the save and spoke about it in the media after the game.
“That Alisson save? That was incredible. I swear to you, I saw the ball going in.. and then it wasn’t,” he told Sky in Italy, per the Liverpool Echo.
The Reds will now play Villarreal in the semi-finals. While Villarreal are a decent team and cannot be underestimated, Liverpool will fancy their chances of seeing off their Spanish opponents.
Real Madrid and Manchester City will contest the other semi-final.
The ultimate Jurgen Klopp quiz: How much do you know about Liverpool’s manager?