''If I hear that from you again, I'll break your jaw,'' Kalac said. ''Just play and worry about what you're doing and not anyone else.''

Petratos didn't back down and tried to excuse his actions by saying he was calling for the pass. But that triggered another passionate response from the coach. McFlynn eventually stepped in between the pair and pulled the young forward away as another teammate told Petratos to ''show respect'' to the goalkeeping coach.

Training returned to normal moments later as Kalac and Petratos calmed down but some players were distracted by the argument. Crook, though, showed no sign of concern over what he said was a common incident at any club's training session, adding the bust-up showed the level of passion within the camp.

''[These are] things that happen on the training field,'' Crook said. ''I've seen punch-ups before - they're things that don't bother me. They're things that happen … in every squad I've ever been in.''

Yesterday's training was mostly a recovery session for the players who took part in Sunday's win against Perth Glory, and most of the first team had already made their way back to the sheds when the argument broke out. Crook had also made an early departure from the training pitch but was immediately told of the bust-up.