Former Celtic manager Martin O'Neill broke a 32-year spell without a Treble at Parkhead.
His 2001 triumph meant he joined only the legendary Jock Stein in winning all three domestic trophies – and so he's well aware of the immortality that awaits Ange Postecoglou if he can deliver the clean sweep this season.
With the Premier Sports Cup already secured in December, Postecoglou is just nine games from delivering what only Stein, O'Neill, Brendan Rodgers and Neil Lennon have accomplished in Glasgow's east end.
Sunday could see them take a monumental step towards that aim in the third league derby of the season against Rangers at Ibrox and victory would make them huge favourites to get over the line in the league campaign.
Then follows a Scottish Cup semi-final against the same opposition just two weeks later.
O'Neill admits he never let any of his players even think about the feat until they swatted aside Hibs at Hampden to complete the set.
And speaking to Clyde 1 Superscoreboard, he said: "It would be a fantastic effort.
"I must admit, I never really thought about a treble up until we had defeated Hibs in the Scottish Cup Final, and you think, 'OK, we've done it.'
"Taking the championship away from Rangers was obviously massive.
"We'd won the League Cup earlier on so we didn't really think about it until the last couple of days and essentially never gave it much consideration until after the match was over.
"When we won the treble it was terrific, great to know that it was the first time since Jock Stein, the immortal Jock Stein had done that.
"So for Postecoglou to be contemplating something like that this year is a terrific effort."
