An unbelievable night in Turin saw 10-man Porto stun Juventus to reach the Champions League quarter finals.
And Reds loanee Marko Grujic was at the heart of the action late on when he wasted valuable time for his team in a classic exhibition of football's darker arts.
The Portuguese side lost 3-2 on the night but progressed after extra-time, recording a 4-4 aggregate draw and knocking out the Serie A giants on away goals.
Cristano Ronaldo and co started the match 3-1 down and found themselves further behind after just 20 minutes when Merih Demiral brought down Mehdi Taremi in the penalty area and Sergio Oliveira stepped up to send the ball past Wojciech Szczesny.
Andrea Pirlo's side struggled to break down the Porto defence but just three minutes into the second half Federico Chisea collected a Ronaldo lay-off and curled home into the top corner.
Porto then went down to 10 men when Taremi was shown a second yellow for kicking the ball away before Chisea then scored again following a cross from Juan Cuadrado with around half an hour left to play.
There were chances for the home side, but the game headed towards extra time with scores level at 3-3 and Porto boss Sergio Conceicao brought on defensive midfielder and Liverpool loanee Marko Grujic to replace Mateus Uribe on the 90-minute mark.
On the 110-minute mark Grujic had a chance to seal the tie for his side but delayed his shot in the box allowing the defence to block.
The game then looked destined for penalties, until Porto midfielder Oliveira blasted a long-range free-kick under the wall and past Szczesny to spark wild celebrations with five minutes to go - Ronaldo turning his back on the shot before the ball flew underneath him.
Adrien Rabiot then scored a header for Juventus three minutes from time but during the incredibly tense final moments at the Allianz Stadium won his team a free-kick close to the byline, going down under a challenge from Rabiot and Porto held on to claim a famous victory.
The Reds loanee went down clutching his face, before looking through his fingers and wryly smiling - knowing he was wasting time and his theatrics saw a valuable minute go by.
You could call it the dark arts, it's the side of football that is never admired by opposition fans and never really spoken about - particularly with the current Liverpool team occasionally being accused of being 'too nice' - but is a tactic that has been employed by even the greatest squads across Europe throughout history to win matches, trophies and competitions.
Grujic's incident has been compared to David Luiz smiling on the ground while pretending to be injured against Manchester United for Chelsea at Old Trafford and when Barcelona midfielder Sergio Busquets had a sly look while rolling around on the ground against Inter Milan.
There are many more examples of the dark arts which can include time wasting, stealing yards at throw-ins, engineering contact or tactical fouls and they can be routinely undertaken by a variety of players in any given side in order to avoid punishment from the referee for persistent fouling of the laws of the game.
To be fair to referees there are players who sometimes get shown a yellow card for committing such actions, while there are many teams who employ what Liverpool manager Jurgen Klopp calls "dirty" tactics , but when you look at the other side of the coin you will regularly see the Reds.
For example, Liverpool have been handed the Premier League Fair Play award for the least accumulative points for fouls and bookings in every season from 2016/17 onwards.
Now, as the saying goes, nice guys finish last and while there is no suggestion Liverpool should be a horrible team and essentially cheat to win games - particularly given the success they have found in recent campaigns - when they have been backed into a corner and are fighting to win game this season, having a player like Grujic in the mix may have done no harm.
