The Roar are currently sitting eighth on the A-League table and are just four points out of the top six meaning a win is vital in keeping their finals hopes alive.
McKay says it is important the Roar players get themselves up for such a big match in front of home fans at Suncorp Stadium.
"We need points and that's really vital," the 27 year-old said. "These are always big games and Sydney is our traditional rivals.
"So we have to go out there with a positive attitude ... and do it for ourselves.
"It's our last home game of the season and the kids are back from school holidays and everyone's in Brisbane," he added.
"It's a good opportunity for everyone to get out and support us.
"I love playing there and I love it when we get a huge crowd, so hopefully everyone shows up."
McKay admitted that Brisbane's recent form against the Sky Blues was fairly good but conceded they are a much tougher prospect this time around.
"Sydney are flying at the moment and have had a lot of success," he said. "But we've beaten them the last few times up here which is pretty good.
"Hopefully we can dent their run and continue our late push for the finals."
Brisbane host Sydney this Saturday night at Suncorp Stadium - kick-off is at 6:00pm local time (7:00pm AEDT).