On Monday, Djokovic looked unfazed for much of the match, though after taking the second set he did stare at a pocket of Rune supporters.
He also looked towards chanting fans when standing by the microphone as he waited for his on-court interview.
“I played in much more hostile environments, trust me – you guys can’t touch me,” he said.
“To all the fans that have had respect and stayed here tonight , I thank you from the bottom of my heart and I appreciate it.”
Rune, for his part, thought it was clear what the fans were doing.
“If you don’t know what was happening, probably it sounded like ‘boo’. But if we all know what happened, it was my name,” said the 21-year-old.
“If he didn’t remember, it could probably sound different for him. I don’t think it played a massive part in the match.”
It is, of course, not the first time a sport star’s name has been bellowed with the vowels stretched out; not even at Wimbledon this fortnight.
When Sue Barker entered Centre Court to interview Andy Murray in his emotional farewell on Thursday, she was met with cries of ‘Suuuuuuuuue’.
And when Joe Root was introduced to the crowd earlier in the tournament, he was welcomed with the same shout that greets his boundaries for England: ‘Rooooooooot.’
Djokovic, who faces Australian ninth seed Alex de Minaur in the quarter-finals, appeared to have seen the funny side of things by the end of his interview.
He signed off by saying: “To all those people that have chosen to disrespect the player (in this case me)… have a goooooooood night.”
But, in a later interview with BBC Sport, he stood by what he had said.
“When I feel a crowd is stepping over the line, I react,” he said. “I don’t regret my words or actions on the court.”