Manchester United posted footage of Cristiano Ronaldo being booed by his own fans prior to the 2-1 loss to Brighton at Old Trafford.
Ronaldo, started as a substitute in Erik ten Hag's first game in charge, which ended in defeat after a first-half brace from Pascal Gross.
The 37-year-old told the club earlier this summer he wishes to leave due to his desire to play in the Champions League but no potential suitors have emerged and he was back in the side for the friendly against Rayo Vallecano last week.
However, he did anger Ten Hag by leaving the game at half-time without permission from the club and the Dutchman said the actions of Ronaldo and other players "unacceptable".
On Sunday afternoon Ronaldo came off the bench as United attempted to try and turn around the result in the second half.
There were plenty of jeers from the disgruntled home fans - and some of it came before the game when Ronaldo made his way out to the pitch.
United posted a clip of the five-time Ballon d'Or winner walking out of the tunnel to warm up with the rest of the substitutes, but boos aimed at Ronaldo were audible.
United's all-time goalscorer Wayne Rooney has said his former club should let Ronaldo leave this summer, an opinion shared by long-time captain Gary Neville.
However, Roy Keane, another man who wore the armband for the Red Devils, believes the club cannot replace him due to a lack of options in attack.
"You can't let Ronaldo go out the door and think Martial is going to be the answer, Martial isn't the answer," Keane said on Sky Sports.
"He's had a decent pre-season? Big deal.
"They haven't got enough options at this moment in time. That might change in the next few weeks but from a footballing point of view, you just have to hold on to Ronaldo.
"You can't let him go when you haven't got the back-up behind it."
Topics: Manchester United, Premier League, Cristiano Ronaldo, Brighton And Hove Albion, Erik Ten Hag
Josh Lawless