The 33-year-old England international and his team-mates head to Wales bottom of the Premier League, four points from safety and with the worst goal difference with ten games left to play.
The Bluebirds sit just a point - and a place - ahead of the Cottagers and Parker admits it is the result which is important on Saturday.
He told getwestlondon: "When you get to this point in the season and you've got two teams at the bottom fighting for your lives, it's not going to be a classic.
"It's going to be one full of energy and desire. I'm not sure how much quality there will be. The most important thing is winning.
"They will have the same mindset and will be looking to do the same. We'll give it our best shot.
"It's the biggest game of the season for us. We need to come out of it with some points."
German tactician Felix Magath is now in charge of the Cottagers following the departure of Rene Meulensteen, who himself replaced Martin Jol, but he is yet to pick up a win after two games in charge.
Parker admits the players are still adapting to the new boss' methods, saying: "When a new manager comes in it takes some time to get used to what they want from you, their philosophy and how they want to play.
"We're still going through an adaption phase but it's gone down really well. We're trying everything we can to pull ourselves out of the situation we're in."