Why was Smith Rowe's goal for Arsenal against Man Utd allowed to stand?

Manchester United fans could not believe their team's rotten luck on Thursday as a bizarre clash between Fred and David de Gea led to Arsenal open the scoring at Old Trafford.
Emile Smith Rowe's goal originally looked set to be ruled out due to a presumed foul on the United No. 1 in the build-up, but it turned out that De Gea was felled by his own team-mate, meaning the strike was legitimate.
However, the Red Devils went home happy as they ultimately prevailed 3-2.
Editors' Picks
- How Gerrard's Aston Villa can stun Man City to hand Liverpool the title
- Origi is leaving Liverpool - but will Salah, Mane and Milner follow suit?
- Why has Chelsea title-winner Oscar never returned to Europe from China?
- 'Barca changed the game but Lyon was here first' - Inside OL's Women's Champions League comeback
Why was the goal allowed to stand?
Logically enough, once it was determined that Fred and not one of Arsenal's players stood on De Gea's ankle, causing him to hit the ground, any question of the goal being ruled out for foul play on the opposition's part is invalid.
The actions of the man in the middle, however, were crucial.
Referee Martin Atkinson had brought his whistle to his mouth just as Smith Rowe released his shot and looked to be preparing to blow for an infraction.
Had he sounded the whistle, play would have to be brought back no matter what the outcome.
But the referee refrained from stopping the action, meaning that while he believed a foul had taken place prior to the goal he was free to ask for VAR consultation and change his mind.
United may feel aggrieved, but they paid the price for breaking one of football's golden rules in stopping and waiting for a free-kick, rather than always playing to the whistle.
'Next level Fred!'
Just over 10 minutes of Thursday's Premier League clash at Old Trafford had been played when Smith Rowe volleyed into the net from distance, with De Gea lying on the ground.
Match official Atkinson originally ruled that a foul had occurred on the goalkeeper, stopping the action while he received treatment between the posts.
After a lengthy pause, though, and on further consultation with officials, Atkinson changed his mind and pointed to the centre-circle.
It appeared to be the right decision, but that did not stop United players remonstrating with the referee in complaint - while on social media the goal also caused plenty of discussion and mirth.
The hosts did ultimately recover from that early setback to take the win in a five-goal thriller.
Goals from Bruno Fernandes and Cristiano Ronaldo overturned Arsenal's advantage and, while Martin Odegaard levelled for the Gunners, Ronaldo was on hand to score his second from the penalty spot 20 minutes from the end and seal a valuable 3-2 victory at Old Trafford.
What’s Fred moaning about?! It was him who fouled his own ‘keeper. 🤣 pic.twitter.com/9lrhWwwpau
— Piers Morgan (@piersmorgan) December 2, 2021
Fred fouling his own keeper to let Arsenal score is absolutely next level Fred
— Football Ramble (@FootballRamble) December 2, 2021
Goal: Emile Smith Rowe
— gunnerblog (@gunnerblog) December 2, 2021
Assist: Fred
Fred accidentally stands on De Gea's foot, who collapses to the floor and Arsenal score into an empty net. The most Manchester United sentence ever
— Project Football (@ProjectFootball) December 2, 2021