Newcastle were agonisingly close to beating the French giants at the Parc des Princes on Tuesday night before a huge call was made.
Tino Livramento was adjudged to have handled the ball, despite it first hitting his chest and then his elbow.
Mbappe stepped up to the spot and fired in to cancel out Alexander Isak's opener for Newcastle to seal a 1-1 draw in the French capital.
It's a decision that has since prompted wide-scale debate about the rules of the game, with many feeling it's an incredibly harsh call.
However, it's not the only goal that raised eyebrows on Tuesday night as Barnsley beat Wycombe late on via very strange circumstances.
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With the clock ticking down, Sam Cosgrove saw goalkeeper Max Stryjek attempting to waste time by slowly picking up the ball.
He eventually did so and was bumped into by the Barnsley striker, with the ball falling from the Wycombe man's grasp as a result.
Cosgrove seized the opportunity and scored his first goal for the club in an empty net, with his celebration seemingly delayed as he wondered if it had stood.
It was certainly a bizarre scenario at Oakwell Stadium, but even Wycombe boss Matt Bloomfield wasn't too convinced it was a foul.
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"I've never seen a goal like it," he said after their third consecutive defeat in League One. "The circumstances are so disappointing.
"Usually when a striker runs at a keeper it's a foul. But at the same time, you've got to hold on to the ball. I saw the reaction I wanted from Saturday, but to lose is so frustrating."
Cosgrove himself was more delighted and with a cheeky grin, he told the BBC: "It's the best goal I've scored."
He went on to explain: "From half an hour in, they were being slow with the ball, borderline time-wasting. The lad's gone down from the corner, the 'keeper, and no one's touched him.
"The ref's given him the ball back and he's waiting for me to come up to him so it's a little bit poor from that point of view.
"I've probably nudged into him, yeah there's a little bit of contact but there's absolutely nowhere near enough for him to drop the ball on the floor."
He added: "Goalkeepers notoriously get a lot more decisions going for them, I suppose they can be a little more vulnerable going up to get balls.
"But in a scenario like that there's absolutely no need for him to drop the ball and to go down in that fashion. So, fair play to the referee and kudos to him for seeing that and probably working on the balance of play, it wasn't a foul."