The R's are back at Loftus Road after two matches away and although they have a decent record at home, Mackie says that the West Londoners will have to be on top of their game as the Baggies pose a real threat.
"We certainly won't be taking West Brom lightly," he told the club's official website.
"They've got some quality players, especially some of the Scottish lads who I know well, so we know it's going to be a tough game.
"It's important for us to get another home win though. Our home form will govern our fate this season.
"We're very much looking forward to the challenge of playing West Brom in front of another packed house at Loftus Road."