Pep Guardiola said Manchester City were "not the team I can recognise" during their early season struggles.
A defeat to Tottenham in November left them languishing 11th in the Premier League, with Jose Mourinho's men going top.
Spurs visit the Etihad Stadium on Sunday morning (AEDT) to face a City team who have not lost in 22 outings across all competitions since that match and sit five points clear at the Premier League summit.
Discussing a remarkable turnaround, Guardiola did not think the reverse at the Tottenham Hotspur Stadium proved to be the pivot point.
Perhaps more damningly, he felt the nadir came the following month, when City followed up a 0-0 draw in the Manchester derby at Old Trafford by being held 1-1 at home by West Brom - relegation threatened opponents who still sacked boss Slaven Bilic in the aftermath of taking that point.
"To be specific, it was after the game against West Bromwich," Guardiola said. "We could've won with two incredible chances at the end but after that game, I felt this is not the team I can recognise myself. I didn't like what I watched, I didn't like what I saw.
"We talked and we said, okay, we have to come back to our first principle. We had to reconstruct the team from that point. What we are as a team, how we had success in the past.
"We had to come back to our game, move the ball quicker, do more passes, stay in position, run less with the ball, do it together. We don't have a specific player to win games, we have to do it together.
"But above all that was the commitment of the players. They talked, they thought, okay, we have to do more and they did it."
The results have been startling, with City winning every one of their 15 subsequent matches - an all-time record for a top-flight English club.
In the 15 games preceding their ongoing streak, City won nine and drew five alongside the Spurs loss.
The arrival of Ruben Dias had already gone a long way to shoring up a defence humiliated during a 5-2 September loss to Leicester City, with City breached six times during those 15 matches. They have let in five during the winning run.
Their expected goals (xG) is actually up from 7.1 to eight, with 10 clean sheets in each batch of games.
It is up front where Guardiola's men have rediscovered their mojo despite the on-going absence of club record goalscorer Sergio Aguero.
City's 40 goals dwarf 25 from the prior 15 outings. Misses such as the ones from Ilkay Gundogan and Raheem Sterling that Guardiola referenced from the West Brom draw are also less of a factor.
During that segment earlier in the season, City were tracking below an xG of 27.7. With the likes of Premier League Player of the Month Gundogan (eight in 15 games), Sterling, Phil Foden (both six) and Gabriel Jesus (five) back in the goals, they are operating clearly above an xG of 32.9.
Tottenham's season is heading sharply in the other direction.
They were eight points better off than City after beating them, but their subsequent 13 Premier League matches read won four, drawn four, lost five.
Counting top division matches only from this period, City have outscored Spurs 33 to 15, having played once more, claiming 38 points to Tottenham's 16.
Guardiola's backline has been breached a mere three times since that last league loss and faced 92 shots at an xG against of 6.6. Mourinho's men have faced 183 attempts on goal and an xG against of 15.91 is a touch higher than their 13 conceded.
Once again, the tempestuous and thrilling back and forth that marked Guardiola and Mourinho's spells in charge of Barcelona and Real Madrid will not be repeated in England, as was the case when the Portuguese took up residence across the city at Manchester United.
For this reason, perhaps, Guardiola was comfortable speaking cordially about his old rival.
"I have a good relationship with him, we can agree or disagree but it's not a big problem," he said.
"His business is Tottenham, or before United, mine is City. We have to handle our team and backroom staff and we don't have time to know what about the other club and could not care less.
"The only concern is what we have to do tomorrow."