Liverpool forward Divock Origi scored his second goal of the night to put Liverpool 4-0 up in the second leg and, incredibly, 4-3 on aggregate against Barcelona.
It was all about the quick thinking from Trent Alexander-Arnold as the young England full-back, who didn't start the first leg at the Camp Nou, fizzed in the corner into the six-yard box.
Origi was the only Liverpool man alert to it with the rest of the Barcelona players preparing to defend the corner.
And the 23-year-old showed just how much he has improved this season, finishing smartly into the top corner despite Gerard Pique's efforts to keep it out.
The Barcelona players looked stunned by the events after being caught out by a moment of genius.
The Belgian would not be able to get a famous hat-trick at Anfield, after picking up an injury late on, but his goals ensured his contribution would go down in history.
