Melbourne Heart coach John Aloisi was unhappy after an unidentified intruder was spotted filming the club's behind-closed-doors training session at AAMI Park on Friday.
Heart – who have only lost one of the seven Melbourne derbies against rivals Victory – shut the doors to the public as they prepared for a clash that is expected to draw a crowd of over 30,000 fans at AAMI Park on Saturday night.
But they were interrupted by a cameraman who was said to be filming Heart's preparations from one of the corporate areas.
The intruder quickly left after being noticed but Aloisi was still annoyed once the training session had ended.
"I did see someone with a camera watching our session," Aloisi told reporters on Friday.
"I'm not sure if he was (someone from) Victory or not. It wasn't too good if it was (someone from) Victory because it's behind closed doors.
"We don't allow you guys (media) in and if they have got someone recording our training session, it is a bit poor. I didn't find out (who it was). As soon as I started pointing, he ran off."
Aloisi said the club would discuss the issue with the AAMI Park staff, insisting they had been shown no respect by the intruder.
"I will discuss it with the club. (It is) something that we'll mention to AAMI Park," he said.
"They know it is behind closed doors and they do their utmost to make sure that no one comes in and sneaks in while we are doing a session.
"We only get to use this (AAMI Park pitch) once every two weeks whenever we play a home game and we don't ask for people not to turn up when we are out at La Trobe (University, the club's base in Bundoora).
"But when we are here, we ask for a little bit of respect. We didn't get it today."
The incident overshadowed Aloisi's pre-match press conference, in which he revealed that the only change to his starting side would be the return of Josip Tadic from a back injury in place of fellow forward Dylan Macallister.
Aloisi feels his side have the players capable of firing the Heart to their fourth win of the Hyundai A-League season.
"I think we have got players that lift that extra bit (for a derby)," he said.
"Maybe it is the crowd, maybe it is the occasion. We have got players who have played in a lot of big games so they know how to deal with that sort of pressure. It is a different sort of pressure. It's not an ordinary game.
"Us coaches might say yeah, it is another game but it's not. The likes of Clint Bolton, Simon Colosimo, Matt Thompson... they have been in these games and they have played a lot of them. They know how to deal with it and know how to prepare well for it."
Heart midfielder Richard Garcia, meanwhile, believes the fixture against Victory is the ideal chance to begin a run of form.
"We want to string a few wins together and try to go on a run, and what better opportunity to do it than against your rivals," Garcia said.
"We're feeling really good. We've had a good weeks training and we're really looking forward to the challenge ahead. It's a big game and everybody likes to play in it."
Heart sit in eighth on the A-League table with 12 points from 11 matches.