Jamie Carragher and Liverpool were left angered after referee Michael Oliver didn't stop the game leading up to Manchester United's opening goal at Anfield.
Alexis Mac Allister went down with a head injury after colliding with Virgil van Dijk just inside the Liverpool half. United picked up the second ball, played on and it led to Amad Diallo feeding the ball through to Bryan Mbeumo, who composed himself before crashing the ball past goalkeeper Giorgi Mamardashvili.
Liverpool's players and Arne Slot were not pleased with Oliver as he didn't pause the game when Mac Allister went down after getting a bang to his head. The Argentina international stayed down while United continued and scored, with Carragher then reiterating the same point while on co-commentary for Sky Sports.
Commentator Peter Drury started: "What we are getting from the match centre is that the referee didn't see the injury and was therefore obviously not able to stop the game."
Carragher added: "He was on the floor holding his head."
The FA rulebook states: "Play is stopped if, in their opinion, a player is seriously injured or receives a head injury."
Mbeumo's goal was his second in the Premier League for United, after finding the net against Burnley back in August. He looked dangerous in the opening half an hour at Anfield, while Amad, Bruno Fernandes and Matheus Cunha also caused Liverpool all sorts of issues early on.
Indeed, Fernandes should have doubled United's lead midway through the first half. Amad set the ball back for the United captain to hit it from inside the box, but he swept his effort just wide.
Cody Gakpo did have an excellent chance to score an equaliser for Liverpool just before that, as he was played through on goal by Mohamed Salah but his strike hit the base of the post and was cleared.
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