Gojko Kacar has hit back at Friedhelm Funkel after the Hertha Berlin boss questioned the defensive midfielder's fitness after international duty with Serbia.
Hertha's 22-year-old anchorman joined Bulgaria international Valeri Domovchiyski in receiving the brunt of club manager Funkel's wrath when he declared his displeasure at the duo's fitness levels upon returning from their respective national side commitments.
Funkel said: "I see them returning in a status of being tired. Probably they are drinking too much coffee or are sleeping until noon when being with their international squads."
But Kacar, who was a £10million target of rivals Stuttgart in the summer, has refuted the accusations of his manager by insisting he did not exceed the recommended caffeine intake while on Serbia duty.
He told Bild: "We are travelling a lot when on duty for our country, we are in hotels and have tough encounters.
"This makes you exhausted. But we have gained qualification for the Fifa World Cup.
"We are clearly not doing too much wrong. Also with Serbia we are having training sessions in the morning and I cannot drink more than two cups of coffee.
"Claims I would not adhere to deadlines with physios and doctors are rubbish. It may be a fact I was tired coming back from Serbia lately, but I gave my best at Stuttgart last weekend.
"Unfortunately it was not enough. I am actually not on top of my game, still I work hard to change this."
Kacar added that neither Hertha's current predicament, which sees them struggling in 18th place in the Bundesliga, nor Funkel's comments have made him consider leaving the German capital club.
"I am not thinking about another club, I am focused on Hertha," he said. "And I will show this to the manager!"