Football moves in fast-forward.
On December 30, Sunderland thrashed Sheffield Wednesday 5-0 at the Stadium of Light to go into the New Year as League One leaders.
Fans sang ' Lee Johnson's red and white army' and 'top of the league' and the atmosphere on Wearside was jubilant.
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It rounded off a month in which Johnson picked up December's League One Manager of the Month, with his side remaining unbeaten throughout the month as they collected 14 points out of a possible 18.
But exactly a month to the day after that emphatic win against Wednesday, Johnson picked up his P45 and that manager of the month award was stuffed in a cardboard box as he cleared his desk at the Academy of Light.
What went wrong? What happened?
A run of just one win - and five points - from five games in January happened, with the 6-0 humiliation at Bolton on Saturday proving the last straw.
Only days before that ill-fated trip to Bolton, Sunderland fans had been looking forward with optimism as the club finalised deals to bring in Patrick Roberts from Manchester City and Jack Clarke from Spurs.
And a week earlier, the fans had been purring over Danny Batth's debut in a 1-0 win against Portsmouth.
But that defeat at Bolton - in which Batth scored a spectacular own-goal - changed everything.
It was the tipping point, but it was not that game in isolation that resulted in Johnson's sacking, it was an accumulation of things.
A run of three league defeats back in October-November had allowed doubts to creep in.
And while Johnson rode out that particular mini-crisis, he was not so fortunate in January.
If conceding an injury-time equaliser at Wycombe was painful, losing at home to Lincoln and being goaded by ex-Sunderland man Chris Maguire - who ended up with a hat-trick - was agony and to make matters worse, Johnson was later sent to the stands.
Conceding another late equaliser, this time against ten-man Accrington, hardly helped matters.
The win and clean sheet against Portsmouth came as blessed relief, but Bolton was a glimpse into the jaws of hell.
Johnson departed with Sunderland having the best home defensive record in the division, and the worst in the division on the road.
The Black Cats are third in the table, a point outside the automatic promotion places and two points behind leaders Rotherham - albeit both of those clubs have games in hand.
The question now is where do Sunderland go from here?
Previously when Sunderland have changed manager mid-season, there has been a general acceptance that the time to judge the new man will be at the end of his first full season in charge.
Phil Parkinson was not sacked after failing to win promotion in his, admittedly Covid-curtailed, first half-season in charge.
Nor was Johnson given the boot after falling short in the play-offs last summer, having been handed the baton midway through last season.
Johnson's successor will not be given that luxury.
Majority shareholder Kyril Louis-Dreyfus' statement following Johnson's sacking contained the line: "We firmly believe that this is in the best interests of Sunderland AFC as we strive to earn promotion this season."
The implication is clear: whoever is appointed will be expected achieve promotion this season.
Johnson was not sacked in the hope that his successor might deliver promotion in 2023.
Parkinson, Johnson, and Jack Ross before them, were given time to reshape the squads they inherited to their liking.
That will not be a factor this time around.
When the new head coach is appointed, the January window will have closed and he will have to work with what he has got.
In any case, the whole point of moving to a sporting director/head coach structure was to bring a measure of continuity rather than the 'rip it up and start again' policy that had previously become the norm.
The idea was that sporting director and head coach would be in sync, implementing a consistent vision so that a change of head coach could be made with the minimum of disruption.
Therefore it stands to reason that sporting director Kristjaan Speakman will be looking for a new head coach who plays a similar brand of high-tempo, attacking, football to that which Johnson's team managed when they were at their best.
The squad has been built around players who play that way, so a radical shift in style would be counterproductive.
Essentially, Speakman is looking for Johnson 2.0 - a head coach who can maintain Sunderland's home record, while tightening up the defence on the road without sacrificing the team's attacking threat.
Whoever gets the job will take over a team and a squad which, under Johnson, has already established a platform for promotion.
Their challenge will be to finish the job that Johnson started.
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