Sunday's Old Firm win at Ibrox moved Celtic six points clear at the top of the Scottish PremiershipAlmost a year to the day, Celtic fell to an abject fourth round Scottish Cup defeat at newly-crowned champions Rangers, ending their hopes of silverware in a woeful 2020-21 campaign.
From that starting line-up, only captain Callum McGregor was present when Ange Postecoglou filed his teamsheet at Ibrox on Sunday.
While the extent of Celtic's rebuild this term makes that believable, a more difficult fact to fathom is that just four players from Postecoglou's starting XI on Sunday featured in August's league defeat in Govan.
Just seven months on, the Celtic line-up included seven changes and five new signings as the Australian watched his players battle to a derby victory that moved the side six points clear at the Premiership summit.
"They've had character from day one," Postecoglou said of his team. "There's real steel to them and there's had to be. We were still putting a team together when the league had already started."
'This team now has a winning mentality'
Joe Hart, Carl Starfelt, Josip Juranovic and McGregor were the only survivors from the Old Firm loss in August, a game that was decided by Filip Helander's towering header.
Five of the seven men who came into the side on Sunday weren't even Celtic players at the time of that defeat.
Winger Jota, centre-back Cameron Carter-Vickers and striker Giorgos Giakoumakis penned deals 48 hours later on a busy deadline day, while Japanese duo Reo Hatate and Daizen Maeda were January acquisitions.
Five of Celtic's starting XI on Sunday hadn't yet signed for the club when they were defeated at Ibrox in AugustMoving in the other direction were Crystal Palace's Odsonne Edouard and Bournemouth's Ryan Christie, who both left for England in multi-million pound deals.
"Back in August, Celtic had Edouard walking around up front, knowing he was going to get a move," ex-Rangers midfielder Charlie Adam said on Sportsound. "Christie was off to Bournemouth a couple days later.
"This Celtic team are different. There's a winning mentality in this group now."
'I'm super proud of the players'
The winning mentality Adam references is evidenced in the form that has catapulted Celtic into a commanding position at the top of the table.
August's Old Firm defeat was Postecoglou's second after just four league games - a third after six followed three weeks later at Livingston.
However, since that loss in West Lothian, Celtic have put together 26-game unbeaten league run - winning 22 and dropping just eight points from a possible 78 on offer.
That form has seen them cleave open a six-point lead over Rangers, who held the same advantage over their rivals at the turn of the year.
"For us, and this group of players, to turn it around in that fashion and the resilience this group have shown, I'm super proud of the players," Postecoglou added.
"Everyone knows [Ibrox] isn't an easy place to come to, they're a good side and they're undefeated here this year. Knowing the consequences and the significance of three points, it was always going to be a battle for us.
"There were going to be times we had to roll our sleeves up. But, like I said, after not getting off to the greatest of starts, to go and win the game is a testament to the character of the players."
Defence shines as Rogic rolls back years
A leaky backline was a source of concern and criticism aimed Postecoglou's way earlier this term.
His attacking recruitment was lauded quickly, but doubts raised over Celtic's defensive frailties and question marks surrounded the £4m signing of centre-back Starfelt from Rubin Kazan.
But the Sweden international has responded from a rocky start to form an impressive defensive pairing with Tottenham Hotspur loanee Carter-Vickers.
As well as a tough beginning to his Celtic career, Starfelt endured a rough first half at Ibrox on Sunday, but the 26-year-old turned in a stellar second-half performance alongside his match-winning centre-back partner.
Starfelt registered the joint-most touches (56) for Celtic, and no player on the pitch bettered his 12 clearances, while Carter-Vickers won seven of his nine aerial duels.
Giakoumakis, Maeda and Jota provided tireless running and endeavour at the top end of the pitch, but the class and composure was provided by one of the old guard.
Postecoglou's compatriot Tom Rogic, who looked set to leave Glasgow for Qatar just over 18 months ago, reminded Scottish football of the influence he can have on the Old Firm fixture in a classy display.
"Ange knows what Rogic is all about," ex-Scotland midfielder Adam added. "He knows when to take time and space. He was the only one in midfield able to take a deep breath, relax and get a bit of quality on the ball."
In his hour on the field, Rogic had more shots (four) and touches inside the opposition box (six) than anyone else on the pitch'Incredible job from Postecoglou' - analysis
Former Celtic goalkeeper Pat Bonner on BBC Sportsound
Postecoglou had to rebuild the entire team from back to front. It wasn't a case of having a striker or a defence he could to rely on - it's a completely new defence and goalkeeper.
He's had to bring all those players in, it's an incredible job he's done. They've won a League Cup and are now on the verge of winning the league. I don't think they'll lose it from this point on.
They still have to play Rangers in the Scottish Cup semi-final, but if they get past that they are in a great position. Imagine he wins a treble in his first season after where they were?
