Everton midfielder Idrissa Gueye was sent off in the 13th minute against Manchester United after clashing with his own team-mate.
After a passage of play that saw United captain Bruno Fernandes narrowly miss the target with a shot from outside the box, the Everton players fumed at one another.
Toffees defender Michael Keane immediately called out Gueye, leading to a confrontation between the two.
Keane threw an arm out in anger, though he did not strike Gueye, leading to the Senegal international appearing to hit his team-mate.
The referee saw the whole incident and showed no hesitation as he brandished a red card for Gueye, though Keane escaped any punishment.
And that seemed to infuriate the former PSG star further, as the red mist descended and he tried to confront Keane further.
Idrissa Gueye was sent off after striking his own team-mate
|REUTERS
Everton goalkeeper Jordan Pickford intervened and restrained Gueye, who eventually made his way down the tunnel at Old Trafford.
VAR took a look at the incident and confirmed that Gueye was sent off for striking his team-mate in the face.
Even after the red card was shown to Gueye, Keane continued the argument and told him to get off the pitch - in rather more blunt terms.
It comes after a tough start for Everton at Old Trafford, who lost Seamus Coleman to injury moments before on his first Premier League start of the season.
Meanwhile, manager David Moyes looked glum after the situation broke out - leaving his side in a dismal state.
Michael Keane continued the argument even after Idrissa Gueye had been sent off
|SKY SPORTS
TV replays showed the confrontation in full, which showed Gueye hit Keane, though the actual action appeared to be somewhat innocuous.
Nevertheless, Premier League rules stipulate that a red card must be shown for any strike that hits the face no matter how hard - and no matter who is struck.
Speaking on Sky Sports co-commentary, former United star Gary Neville said: "How much venom was in that slap? He has been sent off for that. Was it a little slap or a proper whack?
"There is no doubt a hand comes out to the face but it didn't look too much. They might have had to send him off purely because there is a strike to the face.
"He's snapped at his OWN team-mate"
— Sky Sports Premier League (@SkySportsPL) November 24, 2025
Idrissa Gueye is sent-off after raising a hand at Michael Keane 😰 pic.twitter.com/zNIcEU2fA5
"They were not fighting, it wasn't a scrap.
"It could have been dealt with by a yellow. I don't think it needed to be a red."
There have been several instances of team-mates clashing on the pitch, most infamous being the brawl between Lee Bowyer and Kieron Dyer in 2005 at Newcastle.
More recently, there have been clashes between Arsenal's Ben White and Oleksandr Zinchenko and Anwar El Ghazi and Tyrone Mings at Aston Villa.
However, this incident was perhaps not as incendiary as Dyer and Bowyer's shocking moment, but no less shocking.
Even though Everton were reduced to 10 men, the Toffees struck against the odds with a fantastic strike from Kiernan Dewsbury-Hall.
Idrissa Gueye was sent off for striking Michael Keane in the face
|REUTERS
The midfielder, who was signed from Chelsea in the summer, stunned the Red Devils with a sublime strike from outside the box.
The England international picked up the ball in the midfielder before racing forward and curling a strike past Senne Lemmens in the United net to send the away fans at Old Trafford into a frenzy.