The Glory moved into fourth spot after the victory and are now six points clear of Brisbane Roar, who appear the only danger of knocking them out of the top six.
Mitchell believes his side has done enough to clinch a finals berth and has sent a warning to the rest of the league, saying his team will be tough to come up against in the next few weeks.
"I think it would be a Houdini act if they (Brisbane) got in from here," said Mitchell.
"I think once we cement ourselves (in the six) we'll go for fourth spot and if we get it, no one will want to place us that's for sure."
Mitchell also praised the depth of his squad, saying it's the best he has had since he has been at the helm of the Glory.
"It's a credit to Tony Sage. He said what do you need to make the squad better and we've gone out and targeted certain players," Mitchell added.
"I think the depth we now have in the squad is the best it's been since I've been coach."