The Red Devils sparked hopes of a comeback when Anthony Martial scored from the spot to make it 2-1 on aggregate, but a magnificent solo effort from Coutinho killed off the tie seconds before the break, as it meant United needed to score three more times. Per Chris Wheeler of the MailOnline, Klopp said:
"What he did was brilliant. [Coutinho] had a genius moment. It was the most unexpected thing he could do in that situation—a perfect goal. We deserve to be in the next round, there is no doubt about that. I'm pretty proud of the boys."
Here is the goal, courtesy of BT Sport Football, in which Coutinho cut inside from the left, ghosted past Guillermo Varela and lifted the ball over the onrushing David De Gea from a fairly narrow angle:
Klopp elaborated on the moment in his post-match press conference, per LFC TV:
Even the German's counterpart, Louis van Gaal, could do nothing but praise the effort. According to Wheeler, he said: "You have to give credit to Coutinho, it was a fantastic goal. You try to raise the players from the disappointment, but you know and they know and everybody knows that we had to score three times. That's difficult."
Bleacher Report UK hailed the 23-year-old's moment of magic accordingly:
B/R's Sam Tighe and the Guardian's Barney Ronay commented on the incredible skill the playmaker displayed:
Meanwhile, James Pearce of the Liverpool Echo and Goal UK's Melissa Reddy noted the transformative effect it had on the outlook of the game and the reaction it drew from Liverpool's away support:
Indeed, the Brazilian's goal—and the time in which he struck it—put a swift and decisive end to United's hopes of progressing and came at the end of an otherwise excellent half of football for the home side.
The strike was Coutinho's eighth of the season in all competitions, and he would have found the net earlier if not for an excellent save from De Gea.
He also had chances in the second half but failed to truly trouble the Spaniard on those occasions.
Coutinho is known for his ability to produce moments of brilliance out of nothing, but they sometimes disguise the fact he's still yet to add consistency to his game.
His tally of eight goals and five assists for the season put him just one assist away from equaling last year's numbers, but in 31 appearances you'd expect a player of his ability to do more.
That's not to take away from his incredible goal on Thursday, but it would be frustrating if he's not able to harness his full and considerable potential by producing excellent all-round performances each week.