Despite the Ibrox club storming ahead in the Irn-Bru Third Division title race, the Gers have flattered to deceive this term and suffered a William Hill Scottish Cup exit at the hands of Dundee United on Saturday.
They return to league duty with a derby clash against Queen's Park on Saturday and McInnes is sure his nine-in-a-row team-mate will be feeling the pain.
He told SportTimes: "Coisty will be the one hurting the most. He has been in the game long enough to know that you are not going to play well every week or win every game, you are going to lose every so often.
"But that won't make it any easier for him.
"It will be the manner of the performance and how they lost the game that will hurt him the most.
"As a manager, you have to set the tone for the week early and that is what Coisty will do.
"They have another game on Saturday and they need to come out and show a professional, committed performance and put the United game behind them quickly.
"I have not seen a lot of Rangers this season but I know they have won a lot of games in the Third Division and only had a couple of blips along the way.
"They have been professional in the league campaign and that is what they will need on Saturday.
"I am sure they will react the right way and get the three points."
With the Third Division title all but secured, Saturday's cup tie was one of the few remaining highlights of the season for McCoist and his players.
However, the Gers failed to live up to the occasion as they slumped to a comprehensive 3-0 loss.
And the former St Johnstone and Bristol City boss McInnes admits the Light Blues can have few complaints about being dumped from the competition.
He said: "There is no doubt Saturday was a huge disappointment for Rangers. The tie itself was always going to be a big ask.
"Dundee United were huge favourites going into the game and it was always going to be a big test for Rangers.
"It is difficult to go from playing Third Division football all of the season to get to the level that Dundee United have been playing at this year.
"Unfortunately for Rangers, they didn't hit their levels and United certainly deserved to win the tie."