The Parkhead side started the campaign with a new manager in Ange Postecoglou who had no experience of Scottish football and a rebuilding job on his hands.
The 2-1 win at Ibrox on Sunday has put Celtic in a commanding position to win back the league title with just six games left.
“The fact he even had them challenging was impressive enough, but to have them six points clear at this stage is a remarkable effort.
“Only a fool will say it is over. It’s not easy to win a championship, especially the first as it would be for a lot of the Celtic squad.
“Crucially, no-one inside the camp will think it is done. The manager and skipper simply won’t allow that to happen.
“You saw them and heard them after the last Rangers game saying that nothing had been achieved after the 3-0 win and that’s the same here. There are still 18 points up for grabs and Celtic are going to have to keep their foot on the pedal.”