Shanghai: Furious Roger Federer argued with the chair umpire after penalty point punishment that saw the 38 years-old to be deducted a point when he was 3-0 down in the decider.
The umpire punished Federer with unsportsmanlike conduct - something that is rare to see.
Federer lost against Zverev 6-3 6-7(7) 6-3 in the quarter-finals of the Shanghai Open on Friday.
When asked to explain why he had been unhappy with the umpire's decision during his Shanghai Masters quarter-final, the 20-time Grand Slam champion responded:
"So you can write it on Twitter you mean? It would be nice once to write something nice also about the game. Next question."
Zverev, meanwhile, defended Federer, declaring "I think emotions in sports are great", and went on to hail him as "the greatest player of all time".
