When Jurgen Klopp brought on Xherdan Shaqiri against Manchester United, he couldn't have imagined the impact his substitution would have.
With Liverpool getting frustrated at 1-1 and running out of ideas in the final third, the introduction of Shaqiri turned the game on its head, upgrading one point into three.
The 25-year-old fired Liverpool into the lead in the 72nd minute, firing past David de Gea after seeing his strike deflect off Ashley Young and the crossbar.
He wasn't finished there, though, with Shaqiri bagging himself another just minutes later and this time he had Eric Bailly to thank, with the slight deflection taking it past the United 'keeper.
It was Shaqiri's finest performance in a Liverpool shirt so far and he has already proven himself to be an inspired bargain from the summer.
Shaqiri's brace vs Man Utd
He's certainly had his critics in the past - we're looking at you, Gary Neville - but Shaqiri seems to be perfect for a Klopp-managed team.
The Swiss international brings a physical intensity to the game as well as providing a range of passes for Sadio Mane, Roberto Firmino and Mohamed Salah.
However, he also seems the perfect character for this remarkably close Liverpool squad, displaying a special unity with his teammates and manager after games.
Shaqiri and Klopp's funny interview
That was certainly the case against United, with Shaqiri and Klopp embracing as they walked down the Anfield tunnel and also during a post-match interview.
Klopp was being quizzed by DAZN in Germany, when Shaqiri wanted to get involved and the pair quickly began an amusing conversation.
The Liverpool boss jokingly asks: "When did you scored the last time with the right foot? in youth games?"
"'Um at Bayern," Shaqiri responds.
"'Oh that long ago!" Klopp laughs, before proceeding to ask him about Monday's Champions League second round draw.
However, Shaqiri had a superb response in his locker and remarked: "'We have our Christmas party tonight so I'm not sure we are awake then!"
Brilliant stuff. Any German speakers can check out the full interview down below:
Liverpool had plenty to celebrate at their Christmas part on Sunday night, so who knows if Shaqiri had the energy to find out his club's opponents in the round of 16.
Had he arisen in time, though, he would have seen a match of great personal interest to him with Liverpool draw his former team Bayern Munich.
Yes, that's the team Shaqiri reckons he scored his last right-footed goal with.
Although Bayern have been struggling for form in the Bundesliga this season, they still represent a difficult task for Liverpool and Shaqiri will need to be at his very best across the two legs.
Thankfully for him, however, there's still over two months to prepare and Liverpool have a game with Wolverhampton Wanderers on the horizon this Friday.
That gives Shaqiri plenty of time to recover from the Christmas party.
How far do you think Liverpool will make it in the Champions League? Have your say in the comments section below.