The Gers have already been crowned Scottish Premiership, but could register a full campaign without losing a league match if they can avoid defeat against Aberdeen this weekend.
And Durham believes that it would be a monumental achievement for Steve Gerrard’s men given how recently they were being forced to compete in the fourth tier of the Scottish league system.
Speaking on talkSPORT, he said: "Rangers could seal an unbeaten season as champions, and will seal it if they avoid defeat to Aberdeen on Saturday lunchtime.
"They won 3-0 in their penultimate game against Livingston, and I want to say this – it’s not just that they won the title. That’s fantastic for Rangers. It’s all they wanted, to get back to the very top of Scottish football after the years in the wilderness, and Steven Gerrard has led them there.
"But if Rangers go unbeaten, if this happens less than a decade after being in the fourth tier of Scottish football… it’s the biggest ever achievement in Scottish domestic football bar none.
"You can have your Celtic invincible seasons, your treble seasons, whatever you want – did they do it less than a decade after being in the fourth tier? No.
"It’s a club that’s been completely ripped apart, put back together, they’ve had to go through four managers to get to where they are. They’re back on the very top.
"I challenge anybody to deny what I’ve just said there.”