On Monday, Djokovic showed little emotion throughout the match, but after winning the second set, he stared down the Rune fans.
He was also seen shouting at fans as he stood next to the microphone waiting for court interviews.
“I’ve played in a much more hostile environment,” he said. “Believe me, you can’t touch me.”
“I sincerely thank and appreciate all the fans who honored me and stayed here tonight.”
Rune thought it was clear what the fans were doing.
“If you didn’t know what happened, it probably sounded like ‘boo’, but if we all knew what happened, it was my name,” the 21-year-old said.
“If he didn’t remember it, it might have sounded different to him. I don’t think it played a big role in the game.”
Djokovic, who faces Australia’s ninth seed Alex de Minaur in the quarter-finals, seemed to have realised the funny side of the situation by the end of the interview.
He concluded by saying, “To everyone who disrespected the player, in this case me, have a good night.”
But in a later interview with BBC Sport, he stood by his words.
“I react when the crowd crosses the line,” he said. “I don’t regret anything I said or did on the court.”
