After Premier League debutant Alex Jankewitz was sent off just 82 seconds into the game, Southampton struggled massively, especially with United being very confident going forward on the day.
At half-time, the Saints were already 4-0 down, with five other goals coming in the second half as the Red Devils became the second side to win 9-0 against Ralph Hasenhuttl's Southampton in the past 18 months, after Leicester City did so in October 2019.
However, plenty of controversy surrounded the game, with Che Adams being denied an early first half goal due to a very tight offside call, that would have made the scoreline 4-1 at the time.
Yet the biggest decision came for the eighth goal, which was scored by Bruno Fernandes from the penalty spot, as Anthony Martial went down in the box after he felt some slight contact from Jan Bednarek as he was through on goal.
Mike Dean immediately gave the penalty, and a VAR review went on that took around three minutes to be completed.
What was extremely surprising was that Martial was not only given the penalty despite there being very little contact, but Bednarek was also sent off for the decision.
This sparked an outrage by plenty of Southampton players, who were furious with the decision, especially since it meant that their already very limited squad has to play their next game without the Polish defender.
Hugh Woozencroft, who was speaking on talkSPORT's Kick Off along with former England international Danny Mills, was in disbelief at the decision.
"That is probably the worst use of VAR in the history of the Premier League since it’s come in."
Mills then added "This is a shambles, an absolute disgrace. I don't believe it!"
"That has to be overturned, it's an appalling decision. It's not a penalty, it's not a red card; it's a dive as he's already going down."
"I don't think anybody in football would disagree with it being an absolutely shocking decision."
"VAR and the officials have messed it up big time."
Bednarek seemed to tell Mike Dean that even Martial was saying that it was not a penalty, but the referee refused to listen, and he gave the penalty anyway, as the VAR officials had instructed him to do so, and after he had looked at the monitor very closely.