The K League have sent a letter of protest to Juventus after Cristiano Ronaldo was left on the bench for their friendly in Seoul on Friday.
The letter condemns the Italian champions' "arrogance" and "irresponsibility", which is claimed to have been shown "before and after" the match.
The K League apologised to fans the following day as so many left disappointed to have not seen the No.7.
As per the contract, Cristiano was only allowed to sit out the game had he suffered an injury in the warm-up or during the match.
Juventus' reason for not playing the forward is because of his "physical condition".
In the press conference that followed, Maurizio Sarri explained that the player had not played because of an unspecified muscular problem.