The A-League champions will host the decider for the second consecutive season and are hoping a bumper crowd can inspire them to another title
Through the entire finals series, only Central Coast have lost at home, falling 3-2 to Brisbane in the second leg of their major semi, and also dropping a penalty shootout to the Glory after finishing 1-1 at the end of extra time.
Preparing for the Suncorp Stadium decider, where the Roar have lost just four Hyundai A-League games in the past two seasons, Theoklitos warned the visitors not to underestimate the strength of a 50,000-strong Orange Army.
"It's a great atmosphere that (our supporters) generate, and they are like the 12th man," Theoklitos said.
"Perth at home, you can see they won two finals in a row and their home support really inspired them, and we're no different.
"Playing in front of 50,000 at this stadium is an amazing feeling, and we're fortunate enough to have played here last year, so we know what it's about.
"You do stand a bit taller knowing you've got the support of pretty much 50-odd thousand. It's something we're looking forward to."
But while the Brisbane camp were talking about tapping into the energy from their legions of Orange-clad fans, Perth were not shying away from the challenge of playing in front of a blood-thirsty Queensland crowd on a day the club have dubbed Purple Sunday.
Captain Jacob Burns said his side would be just as excited to play in front of a packed crowd and would not lose any advantage from the skewed split of the supporters.
"I've been fortunate enough to play here with the national team in games where this stadium has been full," Burns said.
"It's a wonderful opportunity and a great showcase for our code to sell out this stadium, and I have to say it's probably the best stadium in Australia.
"Once we step over that white line, in my opinion, you block that out and it won't matter if there's more people or less people supporting them.
"As professional players you want to play in front of these crowds week-in, week-out. That's the buzz and I'll be looking forward to putting in a good effort for the boys and hopefully coming away with the right result."
Roar coach Ange Postecoglou, who has spent the finals campaign evading speculation about his future at Brisbane, says the growth of football in the region has been one of his side's strongest achievements.
Expecting around 35,000 people more than the average Roar crowd, Postecoglou said he welcomed the additional fans, hoping their voices could tip the scales on Sunday.
"When I came here two and a half years ago, I realised this is a hard sporting market to crack ... they used to have a three-codes lunch and I used to wonder (why we weren't there), because we play football as well, and now that's all changed," Postecoglou said.
"There will be a lot of people that come to the game tomorrow that don't come here often, and I understand that, but I think we're converting them.
"I guarantee you 90 percent of them will put something orange on, which means before they leave they're putting something on that means they're going to support this team."