The Parkhead club have won only two of their last seven matches in all competitions.
McPake, however, while trying to put his own side’s 5-2 defeat at Ross County behind him, expects the champions to be on top form.
Asked if he felt there was a vulnerability about Celtic at the moment, the 31-year-old former Hibernian player said: “I don’t know. Sometimes you think that and they come and are at their best.
“They have to win every game. They are coming off the back of a defeat and a draw so they are coming here expected to win as they would have been if they had been on a five-match winning streak. They are under a bit of pressure to win so they will be at it, I’m sure.
“It will be a strong Celtic team coming desperate for a win to please their fans.
“We were all disappointed [after Ross County] but we came in, trained and got it out of our system.”