Changing a team's coach in the middle of the season is never a guarantee of anything. In Chelsea's case, it has served them wonderfully.
Since the arrival of Thomas Tuchel in January, the team has improved significantly in the Premier League as well as winning the Champions League final against Manchester City – not to forget the way they eliminated the powerful Atletico and Real Madrid.
Tuchel transformed an erratic and, at times, uncompetitive team into a tremendous block that conceded few goals and imposed their own rhythm.
In the Porto final, Tuchel went against his own principles. In the Premier League, his weapon was a 3-4-2-1 formation that flooded the centre of the pitch. For the final he adopted a 5-4-1 that broke the lines of Manchester City's attacking short-ball possession, their tiki taka football.
It was a tactical lesson but Guardiola helped. Starting without Fernandinho or Rodri seemed unwise and he paid dearly for such an attacking line-up and confused game plan.
Tuchel has now beaten Manchester City three times in six weeks, in three different competitions and with different tactics.
But who is Tuchel? The slender German coach succeeded Jurgen Klopp at Borussia Dortmund, giving rise to all kinds of comparisons, some more justified than others.
Tuchel is more methodical and cooler, and nothing diverts him from meticulous planning and detail, be it the politics of club scouting, approaches to the market, even the nutrition or sleep quality of the players.
This style of management can lead to relationship friction and explains why the 47-year-old Bavarian-born coach has not remained at clubs for lengthy spells.
It led to serious disagreements with Leonardo, PSG's sporting director, notably after the club lost several players for free. Tuchel was fired at Christmas last year, a few months after taking the Paris club to their first Champions League final.
There were similar problems at Borussia Dortmund and Mainz, where he became incompatible with the club board and sporting directors.
We now know that Tuchel met Chelsea owner Roman Abramovich for the first time on the pitch at Estadio do Dragao after the Champions League victory.
We can only hope that, contrary to the past, the relationship between manager and the board will be amicable.
So far, the decision to hire Tuchel has been inspired but it should be remembered he did not choose the current players and a new transfer window is approaching where he will want to be active and in control.
It remains to be seen whether the club understands this and he stays for a long time.
In the meantime, congratulations Chelsea and congratulations Thomas Tuchel.
