Celtic are six points clear at the top of the Scottish Premiership standings - effectively seven once a vastly superior goal difference is taken into account - meaning they would need to lose two and draw one of their remaining five matches to give their Glasgow rivals a chance of defending their championship.
However, Rangers icon McCoist believes such a scenario is possible and he urged his former side to keep believing with the Old Firm sides due to meet again in a pivotal league fixture at Celtic Park on Sunday, May 1.
"I hope so," he said of Rangers' title chances on the talkSPORT. "You've got to keep going. You've got to believe and keep going.
"It would be one of the biggest collapses of all time but you've got to believe it can happen."
Sunday's defeat of Celtic came just three days after a Europa League quarter-final win over Braga as McCoist hailed a "great week" for the Ibrox side while admitting Giovanni van Bronckhorst’s men like to make things hard for themselves.
"I was at the [Braga] game. I was working and it was brilliant," he said.
"The atmosphere was amazing. They should have been home and dry, honestly it could have been 5-0 then we lost a goal right in the last seven minutes to take it to extra time.
"But that's just what we do."