Thomas Tuchel’s whirlwind stint in charge of Chelsea has been brought to an abrupt end.

The Blues’ American owners have shown their ruthless edge and sacked the German 100 days after taking control of the club.

It signals a dramatic fall from grace for the popular boss, who guided Chelsea to Champions League glory in May 2021, before adding the European Super Cup and Club World Cup last term.

We look at where things went wrong for the ex-Paris Saint-Germain coach.

Power struggle

Tuchel, 49, made it pretty clear throughout the summer that he was not thrilled with changes to the way the club was operating.

New co-owner Todd Boehly became the interim sporting director when Marina Granovskaia and Petr Cech, who Tuchel enjoyed strong relationships with, left the West London outfit.

That meant more responsibility for Tuchel in the transfer market and more involvement in signings, which he did not necessarily want.

And reports suggest that while in front of the camera he was talking about managing 100 more games or signing a new deal, behind the scenes he was less keen to talk about long-term plans.

That worried the Blues’ new hierarchy, who wanted to have regular conversations with Tuchel about potential signings and football matters.

In July, Tuchel said: "He [Boehly] is asking for an opinion, he also has players that he likes, there are players offered to him and he can always have our opinion and this is a lively discussion."

Player frustration

There is also a sense that while Tuchel was popular with the fans, his stock had waned within the dressing room.

Lots of that frustration came due to his tendency to play players out of position — putting square pegs in round holes.

Against West Ham, Christian Pulisic and Raheem Sterling started as strikers, Ruben Loftus-Cheek has been used as a right wing-back, while Mason Mount has been shunted to the left of midfield.

All of those tweaks failed to get the best out of his squad and more than contributed to their shaky start.

Only against Tottenham did it feel like the Blues played well this season — and they did not even win that game.

Failing forwards

Tuchel finally landed a forward he wanted last week when Pierre-Emerick Aubameyang signed — which makes it somewhat ironic he only got to manage him for one game.

Failing to get his strikers scoring goals has been one of the biggest criticisms levelled at Tuchel throughout his time at Stamford Bridge.

Romelu Lukaku was signed for £97.5million, yet Tuchel never found a way of fitting him into his side and after netting just eight league goals, the Belgian striker was sent back on loan to Inter Milan.

Fellow summer export Timo Werner was often used out on the left rather than through the middle, Kai Havertz has been converted to a makeshift No9 but never looked fully comfortable in that role, and it smacked of desperation when Sterling and Pulisic lead the line against the Hammers.

Last night, ex-Blues attacker Joe Cole said: "The front three, he made four or five changes in that area, and they all look low on confidence. 

"They are all quality players at Chelsea, but for some reason it's just not happening for the likes of Christian Pulisic and Hakim Ziyech."

Defensive collapse

For all the talk of strikers not hitting their straps, it was at the back where Tuchel’s Blues really lost their way.

In his first 50 games in charge, they kept 31 clean sheets and only conceded 24 goals. In his next 50, they let in 53 and only had 18 shutouts.

The German was fully aware that it contributed to their drop off last season, as they fell away from the top two and out of the Champions League at the quarter-final stage.

In April, he said: "So, like most things in football, it is a mix of bad luck, circumstances, and the opponent making the very most of what we offer them. 

"We also lack the real determination and attitude in the one-on-one in the box at the moment to really keep the actual goals under the expected goals."

Tuchel had little chance to improve it this year either, after losing Antonio Rudiger and Andreas Christensen in the summer, Kalidou Koulibaly arrived in July but until Wesley Fofana joined last week, his options at centre-half were limited.

Writing on the wall

All of this combined meant that Tuchel looked something of a defeated man when he faced the press following last night’s 1-0 Champions League defeat at Dinamo Zagreb.

"I don't know where this performance comes from. It's a lack of hunger, intensity, a lack of determination to win duels, to actually do things on the highest level," Tuchel said.

Those sort of comments would worry any owner, but reports suggest this decision was made before the dismal display in Croatia.

If the Blues had been firing on the pitch, the new owners would undoubtedly have allowed him to continue despite their apparent reservations about his long-term suitability.

But that was not happening and just like previous owner Roman Abramovich, they have proved to be ruthless when needed — now the pressure is on them.

They gave Tuchel more power in the transfer market than any other Blues boss has had for a long time and his replacement will be expected to find success with a squad moulded by their predecessor.

If they get the appointment wrong, the scrutiny will be well and truly on Boehly and Co.