Many Serbians of Krajina (a region in Croatia where Serbs were once the majority) supported his message, backing the country that made them leave.' Meanwhile, at Wimbledon, the three-time former champion reached the quarter-finals where he was to play Kei Nishikori.
'I feel like I'm peaking at the right moment.
The No. 12 seed grew into the match and showed more shades of his old stamina that led him to Grand Slam triumphs, and he'll next face either Rafael Nadal or Juan Martin del Potro, who meet later on Wednesday.
Djokovic had looked in control after the first set on a sunny Centre Court but lost his cool and concentration in the second after a heated exchange with umpire Carlos Ramos.
Djokovic had four break points in the first two service games alone and suffered a Wimbledon meltdown as he bounced his racket off the ground, argued with the umpire, and then went on to lose the second set.
"You're saying in the point if I toss my racket like this I'm ruining the court?"
Nishikori promptly broke serve and then held to go 4-1 up before levelling the match at 1-1 but any sense of a fightback, and the possibility of a first Japanese man in the Wimbledon semi-finals since 1933, was short-lived.
Victory always appeared likely to be a tall order for Nishikori, who has lost to three-time Wimbledon champion Djokovic in 13 of 15 previous matches.
Federer had a match point in the third set at 4-5, 30-40 but failed to take it, before Anderson broke in the following game to earn the opportunity to serve out the set.
"I didn't play badly but in the end there was something lacking, I wasn't able to beat him." said Nishikori.
When asked if he was on a mission to get back to his best, he added: 'That's why I'm here.
"After that he was playing better".
Having reached the semis of 22 of the 24 majors between 2011 and 2016, Djokovic is now closing in on a first final appearance at a Slam since losing to Stan Wawrinka at the U.S. Open two years ago.
"You think I ruined the court by tossing the racket two metres behind the baseline?"
'I didn't harm the grass.
"I think it's not fair, but it is the way it is in the midst of the emotions of a match".
The semi-final will be the 32nd of Djokovic's Grand Slam career but he has had to fight to get there.
The 12-time Grand Slam champion then raised his level in the fourth set and finished with a victor into the corner to book his place in Friday's semi-finals where he was joined by a familiar foe as Nadal won through late in the day.