The once-proud Victory confirmed within hours of Saturday's second record mauling this A-League season by City that Brebner's 16-game stint as head coach was over.

The writing was on the wall after Socceroo striker Jamie Maclaren scored five goals at AAMI Park as City romped to the top of the A-League ladder in emphatic fashion.

Shortly after the humiliation, Victory chairman Anthony Di Pietro confirmed Brebner's time was up.

"It is in the best interests of everyone involved - the club, Grant as a person - we just wanted to make that clear," Di Pietro said.

"Things haven't worked out for a multitude of reasons and there will be a review, clearly, of everything that has happened to lead to this."

Saturday's match started brightly for Victory before Andrew Nabbout's 11th-minute opener for City started another nightmare for Brebner's last-placed team.

Captain Adama Traore saw red on the half-hour mark for a thigh-high challenge on Nabbout, and could face an extended ban after making contact with referee Chris Beath's arm as he argued the decision.

Nabbout then won a penalty which began Maclaren's amazing night.

The 27-year-old, playing in his 50th game for City, added four more in the second half to take his tally for the season to 19.

It's just the second time in A-League history a player has scored five goals in a single game after Victory legend Archie Thompson's remarkable display in the 2007 grand final against Adelaide United.

Brebner, who played in that grand final win during his storied playing career with the Victory that included two championships and two premierships, said his position was no longer tenable after such a horrific campaign at the helm.

"Sadly my expectations and the club's expectations are a lot higher than the position we sit," he said.

"The conversation the chairman and I had, we both were on the same path.

"From my perspective, this club will go on and this club will come back bigger and better than the situation we're in just now."

Di Pietro said it was undecided at this stage who will take the reigns in an interim basis with a decision to be made in coming days.

While Victory are at an all-time low, City's win lifts them to the top of the table.

Coach Patrick Kisnorbo was however eager to emphasise his team is yet to achieve their goals for the year.

"Just because of the result, there's still things that need to be done," Kisnorbo said.

"It's a long season. We need to keep working.

"We need to work harder, we need to be more efficient, to improve. There's no way we're getting ahead of ourselves."

Australian Associated Press