The Dens Park side come into the match having climbed back into the play-off spots with a confident 2-1 midweek win over Inverness CT.
Dundee have had their difficulties this season, starting with the opening day 6-2 thrashing at Hearts.
They did respond with a 3-1 victory in the return match at Dens.
McPake believes it will be a different game this time around, even if Dundee will be missing Charlie Adam who is self-isolating.
“A lot has changed for both teams since that first game at Tynecastle,” he said.
“This will be very different. They have had players come in since then, as have we.
“We just didn’t show up that night and we know that can’t be the case this Saturday.
“We want to be on the front foot and have a go at them.”