It felt like déjà vu for Liverpool fans last night. Back playing in the Champions League, the Reds were struggling to break the opposition down before a moment of magic from a scouser broke the deadlock.

A decade ago it would have been Steven Gerrard stepping up to make dreams a reality for the Liverpool faithful. Now, on his debut in European competition, it was Trent Alexander-Arnold.

The 18-year-old, filling in for the injured Nathaniel Clyne, curled home a perfect free-kick to put Jürgen Klopp's side ahead. With multi-million-pound players huddled around the set piece in the form of Roberto Firmino, Jordan Henderson and Alberto Moreno, it showed great confidence for the teenager to step forward when Liverpool were in need of a moment of pure inspiration.

Speaking on BT Sport, Gerrard was vocal in his support of the right-back: “I know this kid well. He going to be a top, top player.

“I think Nathaniel Clyne [currently injured] has to be very, very careful this season because he's already breathing down his neck. And performances like tonight [and] he's letting Jürgen (Klopp) know he's ready for the big time.”

Up until that point in the match Liverpool had struggled to really impose themselves in Germany. Hoffenheim, who shocked many with their attacking line-up, were dominating the ball, had the Reds chasing shadows from time to time and would have had a lead to defend had it not been for Simon Mignolet between the sticks.

Former Leicester City striker Andrej Kramarić saw his poor penalty effort easily saved and the Belgian keeper followed that up by smothering a Serge Gnabry effort.

Klopp's men looked dangerous on the break but it was a risky game; they had nothing to defend.

That was until Alexander-Arnold, who is included on our list of the ten best teenage footballers in Europe, stepped up after Sadio Mané's driving run from midfield was halted illegally and the Reds had a free-kick 27 yards from goal.

Even without the goal to his name, Alexander-Arnold was arguably second only to Mané in terms of performers against Julian Nagelsmann's men. He was composed on the ball, an outlet down the right even when isolated and, until Hoffenheim finally breached the defence, superb defensively.

He covered his centre-backs well, he positioned himself intelligently and he was arguably the best player in the defensive unit on the night. However, there's a black mark against his name in the eyes of many after he was on his heels claiming for an offside instead of playing to the whistle.

Had he been switched on there's a chance Liverpool would have walked away with a clean sheet and Mark Uth wouldn't have had the time to steady himself and fire past Mignolet.

Should Dejan Lovren have stepped up? Probably. But Alexander-Arnold could see Uth positioned in the blindside of Jöel Matip and the youngster didn't drop to get in line with his right sided centre-back.

It's a learning process for the Liverpudlian, and you can guarantee it won't be a mistake he makes again.

It's ironic that in a week fans of the Merseyside club have been voicing their concerns about the depth of the squad, it's a ‘squad' player who turned out to be a match winner in their all important Champions League tie.

Had Clyne been fit would Alexander-Arnold have started? There are valid points to suggest he should; he's more of a threat down the right and he's better on the ball in the final third, but these points are subjective and it doesn't mean Klopp has the same opinion.

Furthermore, if Barcelona transfer target Philippe Coutinho didn't have a ‘bad back' he probably would have taken that free-kick. He may have scored and Liverpool may have won, but Alexander-Arnold needed to show he's ready to be a starter and he can be relied upon on the big occasions.

It caps off a remarkable 2017 for the youngster. He started away at Old Trafford in January when James Milner was injured and Klopp could have easily opted to play the former Manchester City man as his right sided full-back in a must not lose game.

He trusts Alexander-Arnold, though: “He is an incredible young player,” the Liverpool manager said in his press conference. “I told him he had to take it – he can shoot free kicks better than I ever could. But I don't want the credit for it!

“I have to say for an 18-year-old, who has the balls to take a free kick like that, it is rather more exciting and interesting for me than a little mistake he makes.

“I told him to take it because I watched him many times for the Under-23s last season. He took the free kicks then and, by the way, the goal is the same size.

“There is a big challenge after training between him and Ben Woodburn. They are both good and both improving. It was a bit lucky as the wall didn't jump but it was a very good free kick and very important for us.”

Liverpool have a serious player on their hands. He's played as a number six for the Under-23's and Liverpool coach Pepijn Lijnders once called him his “very own Ruben Neves”.

Alexander-Arnold can play in any third of the pitch, and he's versatile and intelligent to play any of those roles well. There could well be another Captain Fantastic at Anfield in the future.

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