The young right-back put his name up in lights by scoring a 30-yard free-kick in Liverpool’s Champions League play-off.
Jurgen Klopp’s men won their first leg away to Hoffenheim 2-1.
And it was Alexander-Arnold who surprisingly gave the Reds the lead with 10 minutes to go in the first half.
Emre Can and Alberto Moreno left it to the defender to strike low into the bottom corner.
The 18-year-old impressed in Germany and helped Liverpool take an advantage back to Merseyside.
The teenager was delighted with his contribution in his first ever European appearance.
“Obviously it’s a thing of dreams to make your European debut for your boyhood club," Alexander-Arnold told BT Sport.
“And to mark it with a goal as well was very special for me. But, more importantly, we got the win.
“We’ll still be a little bit disappointed with the late goal, but it’s always good to take a lead back to Anfield.”
On his free-kick, he added: “I kind of got egged on to do it, to be honest. I didn’t put my hand up at first.
“But I had the confidence to finally take it and it paid off!”
A Havard Nordtveit own goal with 15 minutes left had almost made it the perfect night for Liverpool.
But Hoffenheim still have a chance of turning the tie around next Wednesday after pulling one back in the 87th minute through Mark Uth.
