Sometimes even the best coaches find it hard to explain football's fluctuating fortunes, the ebb and flow of form and fate that can change so significantly from one season to the next.
Saturday marked the anniversary of Jose Mourinho's appointment as Tottenham's head coach and he celebrated by leading them to the top of the Premier League, a lofty position considering they were 14th when he took over.
This time last year Manchester City were chasing leaders Liverpool and Leicester City, after winning nine of their first 13 games with a goal difference of plus 23, on course to finishing as runners-up with another century of Premier League goals.
Now they are in the bottom half of the table, with only three wins from eight games and a goal difference of minus one. A team who have averaged more than 100 goals in each of the past three seasons are on course to score fewer than 50 at their current strike rate, and they are falling alarmingly away from a title challenge.
The look on Pep Guardiola's face spoke volumes, as he struggled to explain his team's decline.
"We are not a different side to the one that scored over 100 goals last year. Certainly 90 per cent of the forward players are the same. Football is like this, sometimes one season is completely different to another one, and we have to find a way to play," the City boss said.
Mourinho has found a way to take Tottenham up a notch from the team he inherited, who went so close to winning trophies under Mauricio Pochettino but finished as runners-up in the Premier League and Champions League.
There was a steely determination about the way they beat City, happy to play "rope-a-dope" by defending deeply, soaking up all City could offer and then hitting on the break.
Knowing they would have few chances to score, Tottenham's counter-attacks were swift and decisive, as if choreographed in advance. Son Heung-min, helping to protect right back Serge Aurier in a 4-4-2 formation, opened the scoring after five minutes when he blindsided Joao Cancelo, who had switched off, and slid the ball through Ederson's legs.
He had been supplied by Tanguy Ndombele, deployed in attack alongside Harry Kane, a tactic that surprised Guardiola and his players, who struggled to contain either man.
When Ndombele was replaced by Giovani Lo Celso in the 64th minute, Kane led yet another swift counter-attack and set up the Argentinean to score Tottenham's second, killer goal within 35 seconds of his arrival.
Asked if the substitution was brilliant management, Mourinho, in keeping with his latest self-styled title of 'The Humble One' replied: "No, it was luck."
The Portuguese was at pains to downplay Tottenham's ascent to the summit, and quick to pay tribute to the groundwork Pochettino laid during his tenure.
"Being 14th last season was a fake position, a temporary 14th. The work they did before, Pochettino and the players, was fantastic. I'm happy with the evolution since then. I knew where I could improve the team. But this position could be fake. We could lose two games and be mid-table."
Eric Dier was there at the start of Pochettino's period and says Mourinho has added an edge of ruthlessness.
"I don't think teams enjoy playing us," said Dier, who was outstanding in central defence alongside Toby Alderweireld. "I think we're physical, aggressive, determined, we've got a good attitude and the manager has definitely brought an extra edge to that.
"He's more demanding in certain areas and ruthless with you individually and as a team so he's definitely increased that."
Critics have used the term 'Spursy' to describe how previous teams have fallen short with the winning line in sight, but Dier bridles at the word.
"It's frustrating because there were seasons where we finished second in the league and yet people called it Spursy. We just didn't manage to win it (the title) and people were calling that Spursy. I don't believe this team has had that tag for a long time."
The Amazon Prime documentary All or Nothing captured a Mourinho team-talk shortly after he took over suggesting his players were too nice, and needed to be more "nasty".
Again, Dier refutes the claim. "I think we've always had that aggression. From the time I've been at Tottenham, I feel like we've always performed in these big games. Maybe we've not always got the results, but we've always performed.
"For me, it applies more to games like West Brom away when it's really important to be a bit nasty, a bit ruthless. Those are the games we've suffered more in, difficult games away from home against difficult sides. But this time we've gone there and managed to win 1-0."
The only dark cloud for Mourinho on Saturday was a serious-looking groin injury sustained late in the game by Alderweireld, who could be out for some time. But Mourinho has fewer problems than Guardiola, who has to find a way to get his side scoring again.
"We know 10 goals in eight games is not good enough," said the Catalan, who said City cannot bank on an imminent return from injury of Sergio Aguero.
The club's record scorer returned after a long hiatus to face West Ham last month but had to be withdrawn at half-time with a recurrence of the problem. He was an unused substitute on Saturday.
"I'd love to have Sergio back but he is not going to solve the whole situation. He is 32 and was injured for five months, a difficult and dangerous injury. He came back, played 50 minutes and was injured again, so we have to be careful.
"We have to find in this moment a way to play, and we are going to get better."
© Daily Telegraph, London