Melbourne City won't be thinking too much about Patrick Kisnorbo's shock Melbourne Victory departure and instead focus on avoiding a second consecutive derby embarrassment.

Former City boss Kisnorbo this week quit Victory just seven games into the A-League Men season - and days out from Saturday's derby at AAMI Park.

"I was like 'wow'," City coach Aurelio Vidmar joked.

"It's football, isn't it? So didn't expect it, and I think it was a surprise, like for everyone, and it is what it is.

"Doesn't change anything in terms of what we're doing, who's on the bench, who's on the park - it's exactly the same for us."

Defender Nathaniel Atkinson is wary of Victory's response under interim boss Arthur Diles.

"Obviously they want to come out and prove a point with the new coach and I'm sure he wants to get off to a good start, and it's up to us to stop that," he said.

Vidmar conceded it was hard to predict how Victory would react.

"That's probably one thing we can't control. We don't know what's going to happen in terms of how how they are mentally," he said.

"But at the end of the day they're professional footballers, and they're up for a derby.

"So we're prepared in that way, regardless who's sitting on the bench as their head coach.

"It's a derby. It's a huge game and it's going to be super competitive. And that's how we've prepared."

Kisnorbo's departure comes less than two months after he led Victory to a resounding 3-1 win over City.

Victory led 3-0 within 25 minutes as City crumbled.

"Well, we certainly had a big discussion about making sure that it never happens again after that game," Vidmar said.

"But that 30 minutes was probably our worst 30 minutes of football all season, and the game was over by then.

"And so we have to be absolutely 100 per cent be ready for all the small details of the duels and 50-50s (of) just games and derbies where sometimes the ugly things are the things that matter.

"And that's what they had on the upper hand on us in that first game, and we have to make sure we at least get that right."

Vidmar refused to say whether he would stick with young goalkeeper Patrick Beach, who made a costly error against Auckland, or turn to veteran Jamie Young for the first time this season.

City will be without Mathew Leckie and Marco Tilio who have both had setbacks with their respective hamstring injuries.

"Probably not going to make a real clear decision until the new year to be honest, so I can't give you a time frame," Vidmar said.

"They're jogging, but not doing a hell of a lot of high speed, where we confidently can say that they're ready."