Charlie Adam reckons it's clear Rangers have established a psychological hold over Celtic.
The former Ibrox star reckons Steven Gerrard's side have got in their rivals' heads over the course of the season and believes signs the Parkhead club would implode were apparent last summer.
Rangers have cantered to the Premiership title and are unbeaten against Celtic this season, with the Parkhead side missing a slew of chances in a Scottish Cup defeat in Govan 10 days ago.
And, ahead of the two sides' final Premiership meeting this Sunday, Dundee midfielder Adam insists improved performances mean nothing if they can't start producing results once more.
He told Sky Sports: "Looking back to last summer and rumblings about players wanting to leave (Celtic), I think Rangers have been focused; focused on the job each individual needed to do.
"The big job was to stop 10 In A Row and they did that. There's a group of players who were hungry in there.
"With the goings on at Celtic, the disappointment of some results and players wanting to leave in the window and it never materialised. I think that had an effect on the dressing room.
"Rangers just kept going about their business. They showed with the quality they have on the pitch as well. They had unbelievable performances.
"When you come up against Celtic you've got to be at it and every Old Firm they have been.
"Listen, Celtic have done well in the last couple of Old Firm games, which is expected but at the end of the day it's all about winning games and Rangers have managed to do that.
"Rangers are in Celtic's heads because of what they've done. But come Sunday, form goes out the window, I've said it a number of times.
"It's how you set up. We know Rangers will play 4-3-3.
"Will Celtic go with the diamond again? They've had a little bit of success, performance-wise, over the last couple with that."
