Thomas Tuchel's arrival has completely flipped the mood at Cobham from sombre to hopeful.
The German's Chelsea tenure began with a frantic first 24 hours in which he signed his contract on Monday afternoon before quickly running out onto the training pitch for a 6pm training session with his new team that was focused primarily on tactics but also featured a lot of work with the ball.
In between drills, Tuchel also made sure to briefly introduce himself to each and every player before wrapping up the session with a practice match.
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The following day, Chelsea assembled at the team hotel ahead of their Premier League clash with Wolves at Stamford Bridge and Tuchel informed the squad of his line-up, which featured mostly experienced players in a 3-4-3 formation.
"That was a totally unfair team selection because I had no reason for any of the players who did not start to explain why they were left out," Tuchel admitted after the 0-0 draw, which was why he spoke one-to-one with those either left on the bench or excluded from the squad completely.
"You should not read too much into it," he told reporters of his starting line-up. "We have to get to know each other and, in the middle of the season, that was the reason [for the team selection] – nothing else."
Thursday was set aside for recovery, while Friday featured a lighter session involving matches with miniature footballs. On the eve of Sunday's visit of Burnley, Tuchel turned his attention back to tactics.
One prominent criticism of Lampard's management in the final six weeks of his reign was that it was allegedly blighted by a drop in intensity in training, which carried over into big matches.
So, perhaps it is no coincidence, then, that Tuchel has been keen to present a positive image to his squad in order to lift their spirits and raise their energy levels.
Several insiders have told Goal that he has been engaging, enthusiastic and charismatic, so as to immediately banish the sense of doom and gloom around Stamford Bridge.
"For me, it is crucial to create a certain special atmosphere, and bond daily here at Cobham and in the dressing room too," Tuchel said. "But with the current Covid-19 situation, we have social distancing, so that's not easy.
"At the moment, we are using three changing rooms for the team, we can't have everybody in the gym together at the same time, we have to adapt and, for me, we can't do big celebrations in training when we play six versus six.
"All of these little details that maybe we usually don’t think about, they make a big difference in creating a certain bond, a glue, between the players. You need that special atmosphere to take into the dressing room and onto the pitch."
Still, his optimistic approach has helped resolve the dressing room divisions which surfaced during the final weeks of Lampard's tenure.
The Englishman had long been aware of the potential pitfalls of having such a large squad. He had called on the club to offload those deemed surplus to requirements in order to reduce the amount of players he would have to exclude from his matchday squads.
However, there was also a feeling among certain members of the squad that Lampard's team selections were not reflective of certain players' performances. Some of those upset by their lack of game time felt the former midfielder had his favourites and would pick them irrespective of their form.
It was also claimed that Lampard didn't talk much to his fringe players and it is telling that Tuchel's approach to date has been one of inclusion and transparency. He has sought to maintain an open dialogue with every member of the dressing room.
The German's fluid tactical approach, meanwhile, means that the door remains open to everyone, given he is willing to change formation on a match-by-match basis, which is why he wants at least 22 players available for selection for every game, given Chelsea are still alive in three competitions.
Consequently, he isn't pushing for any player to leave in January, stating: "I have the feeling right now that the guys deserve to be trusted and I want to trust everybody."
The net result is that none of Chelsea's squad players are actively seeking moves before the January transfer window closes on Monday – aside from teenage midfielder Billy Gilmour, who Tuchel has no problem allowing to leave on loan for six months.
The Scot is understandably desperate to represent his country at this summer's European Championship but he won't be selected by the manager Steve Clarke unless he is playing regular first-team football.
Despite his willingness to let Gilmour leave, Tuchel is a big admirer of the former Rangers youth team star, as he demonstrated with his in-depth knowledge of Gilmour's game in a press conference on Thursday.
Of course, Tuchel and his backroom team know some players better than others. Thiago Silva and Christian Pulisic have previously played under the former Borussia Dortmund and Paris Saint-Germain coach, while Tuchel's assistants have worked with Timo Werner in the past.
It's also worth noting that Tuchel tried to sign both Jorginho and Antonio Rudiger for PSG this summer and even asked about the possibility of taking Andreas Christensen to the Parc des Princes on loan.
This forensic knowledge of the Chelsea squad even extends to academy players such as Tino Anjorin, whom Tuchel has been speaking with regularly.
The 47-year-old has also thanked the staff at the training ground, with many of Lampard's old team having stuck around to help Tuchel and his assistants Zsolt Low, Arno Michels and Benjamin Weber settle quickly into their new surroundings
Low and Michels have replaced Jody Morris and Chris Jones in coaching roles, while Weber is a data analyst. In addition, Joe Edwards and Anthony Barry have played particularly key roles in aiding Tuchel's acclimitisation, although the latter is reportedly close to becoming Fleetwood Town's manager in the near future.
In summary, then, Tuchel is already starting to feel at home and he's happy with the players he has at his disposal. As a result, he's not engaging in transfer talk, even if it is felt that the club is already looking at potential summer targets, such as Dortmund's Erling Haaland, Leipzig defender Dayot Upamecano and David Alaba, whose contract with Bayern Munich will expire in the summer.
Tuchel's immediate concern is collecting his first three Premier League points against Burnley on Sunday.
He's already made a positive impact off the field at Chelsea; now it's time to pick up a positive result on the field.