The Light Blues had a game in hand with nine fixtures left before the SPFL handed the Hoops the league on a points-per-game basis.
Rangers attempted to block the move, but a majority of the other clubs across the divisions voted in favour of the board’s decision.
Celtic have now wrapped up nine titles in a row and a looking forward to making it 10 next term.
Rangers will pull out all the stops to prevent that from happening, but Halliday believes his former side could have stopped Neil Lennon’s men if the season was completed.
“There were still two Old Firm games to go, I’m not going to sit here and lie, Celtic were the favourites to go on and win the title, but Rangers have won two league titles on the last day of the season – when Celtic could have beat Motherwell,” the midfielder told PLZ Soccer.
“Rangers have been seven points clear going into a title race and ending up losing the title so it was a never say never scenario. Celtic were the favourites but as players we’re always going to think we can claw it back taking it a game at a time and try beat them.
“Going into two Old Firm games, both of them being must-wins but obviously it got taken out of anyone’s hands by the SPFL making the decision for everyone so it’s all guns blazing for Rangers going into next year now.”
Halliday’s comments have caught the attention of Celtic legend Chris Sutton, with the former striker reacting thus to it on Twitter:
I love Andy🤣🤣 https://t.co/DrtXGhWBjA
— Chris Sutton (@chris_sutton73) June 4, 2020
The 28-year-old was released by Rangers last week after five seasons and playing 152 games at the club and is on the lookout for another club, with a move to the MLS touted.