Gareth Southgate described the reaction of some England supporters towards Harry Maguire as "an absolute joke" after the defender was booed before kick-off on Tuesday.
Manchester United captain Maguire started the Three Lions' victory against the Ivory Coast, as goals for Ollie Watkins, Raheem Sterling and Tyrone Mings secured a 3-0 success at Wembley.
The centre-back has been a key performer for Southgate since breaking through into the senior set-up, and he was named to the UEFA Team of the Tournament for his performances at Euro 2020.
Yet since scoring in England's penalty shoot-out loss to Italy in last year's final, Maguire has struggled for form at club level, and has often found himself a scapegoat for United's on-field issues.
Those frustrations translated themselves into audible jeers from sections of the home support on Tuesday, leaving Southgate to launch a passionate defence of his player at the full-time whistle.
"I thought the reception was a joke, an absolute joke," manager Southgate said. "The way he has performed for us has been absolutely phenomenal.
"I don't get it. We're either all in this together or we're not. He's in an England shirt and [...] you support a player in an England shirt regardless.
"When you've played at the level he has for us and put the performances in he has, it should be total commitment behind him. I don't get it at all.
"His performance was pretty faultless really. He stepped out from the back really well for his first goal, was involved in the second one too.
"The team are totally united. We recognise everyone has difficult moments, but he's a top player and he will come through it.
"They are real England fans and some are influenced by whatever – social media or players that played previously who are influencing opinion.
"The club situation is obviously very difficult, but he's in an England shirt. I remember decades ago a few players being booed in an England shirt, and it's never been acceptable to me. Fans should always get behind their team."
Jack Grealish also came to Maguire's defence, with the Manchester City attacking midfielder hailing the defender's creative prowess as crucial to the Three Lions' success against Ivory Coast.
"Personally I think it's ridiculous," Grealish said. "Harry's been unbelievable for this country. Our first two goals have come from him.
"Not every centre-back can have those qualities. It was ridiculous for him to get booed, and it wasn't something the team liked one bit."
