Novak Djokovic accused British fans of disrespect during Serbia's Davis Cup quarterfinal victory in Malaga on Thursday.
The 24-time Grand Slam winner said some fans had tried to annoy him during his straight sets win over Cameron Norrie and snapped at them when they drummed loudly during his post-match interview, telling them to shut up.
“Learn how to respect players. No, you shut up! No, you be quiet!” Djokovic told the fans as they drummed.
"That's disrespect but that's something you have to be prepared for in a Davis Cup," he later told reporters.
"It's normal that sometimes fans step over the line. In the heat of the moment sometimes you react too and you... show that you don't allow this kind of behaviour.
"I mean, they can do whatever they want but I'm going to respond to that. They were trying to annoy me the entire match, so yeah, we had a little bit of a chat in the end," he added.
Djokovic said he was not feeling fresh after a long season but wanted to end the year by helping Serbia with the Davis Cup.
"Being there on the court for my country is always extra push, extra motivation," added the 36-year-old world number one, who is looking to complete a remarkable year after winning three Grand Slam titles and the ATP Finals.
"Part of me looks forward to rest and recalibration and leave the racquet on the side but right now I cannot allow myself to enjoy those thoughts about holidays."
Serbia face Italy in the semi-finals on Saturday
