A disappointed Juergen Klopp turned off the TV when he heard fans of his former team Liverpool booing Trent Alexander-Arnold, who is set to leave this summer after two decades at the club, during a 2-2 home draw with Arsenal earlier this month.
Liverpool-born Alexander-Arnold, who joined the club in 2004 when he was six, debuted for the senior team when Klopp was the manager.
The 26-year-old, who is regarded as one of the best right backs in the world and can also play as a midfielder, has made 353 appearances for Liverpool, winning the Premier League, the Champions League and the Club World Cup during Klopp's tenure.
"I watched the game when he came on and I heard the booing," Klopp said at a fundraising event for the LFC foundation on Friday.
"I am old so I thought it might be my hearing, so I switched up the volume ... I needed another 10 seconds to realise and I switched the TV off. I honestly couldn't have been more disappointed in this moment. This is not us, 100% not us."
England international Alexander-Arnold also featured prominently as Liverpool won the Premier League again this season under new manager Arne Slot.