The officials handed the visitors a penalty in stoppage-time after a shot by Diogo Dalot hit the arm of Presnel Kimpembe, which prompted a review with VAR – controversially awarding Ole Gunnar Solskjaer's side a penalty at the death.
Marcus Rashford converted on the spot to clinch the last-gasp victory for Man United, eliminating the French side from the Champions League.
"That is a disgrace!" Neymar wrote on his Instagram Stories alongside a screenshot of the alleged handball. The Brazil forward missed the match due to injury, though was in the stands and didn't hesitate to make his thoughts known.
"And UEFA still pick four guys who know nothing about football to review the VAR decision in slow motion... that handball simply doesn't exist!
"How do you handball behind your back? Ahh.. go f*ck yourselves."
It looked as if Man United were tasked with the impossible feat of overturning the 2-0 scoreline away at the Parc des Princes after PSG's victory at Old Trafford in the first leg.
Though Romelu Lukaku opened the scoring for the visitors after just two minutes, the home side looked to have found their feet following Juan Bernat's equaliser not long after.
The Red Devils looked ready to inflict an upset, however, once Lukaku scored his second goal to make it 2-1 for the visitors after a mistake from Gianluigi Buffon. With the score still 3-2 to PSG on aggregate until the end of full-time, though, it looked as if Man Utd were about to crash out of the competition at the last 16 stage.
But PSG were minutes away from securing an aggregate victory when Dalot's shot bounced off of Kimpembe's arm right at the end of full time. Following a lengthy consultation with VAR, the referees decided that it was a handball offence committed by Kimpembe and Rashford converted his penalty to send United through on away goals.
It was the first time that a club managed to overturn a 2-0 deficit in the Champions League having played the first leg at home, and Rashford's side ensured that Solskjaer's side advanced to the quarter-finals in the most remarkable – and dramatic – way imaginable.