London, Sep 7 : In an unprecedented move, Chelsea have announced to sack their head coach Thomas Tuchel just hours after losing their Champions League debut 1-0 away to Dinamo Zagreb. Tuesday's defeat follows a disappointing start to the season, which had also seen the club lose to Leeds and Southampton in the Premier League. Furthermore, Tuchel was also involved in an ugly touchline incident with Tottenham coach Antonio Conte after their sides drew 1-1 earlier in the season. The former Paris Saint Germain coach had only been at the club since January 2021 when he replaced Frank Lampard. Last season, Tuchel took Chelsea to the Champions League semifinal, before losing to eventual winners, Real Madrid, and the third place in the Premier League. Chelsea also reached the FA Cup and Carabeo Cup finals, both of which they lost to Liverpool on penalties. The then Chelsea's Russian owner, Roman Abramovich sold the club this year to new owners, who are led by Todd Boehly. "On behalf of everyone at Chelsea FC, the Club would like to place on record its gratitude to Thomas and his staff for all their efforts during their time with the Club. Thomas will rightly have a place in Chelsea's history after winning the Champions League, the Super Cup and Club World Cup in his time here," the club said in a statement. "As the new ownership group reaches 100 days since taking over the Club, and as it continues its hard work to take the club forward, the new owners believe it is the right time to make this transition. Chelsea's coaching staff will take charge of the team for training and the preparation of our upcoming matches as the Club moves swiftly to appoint a new head coach," it added. "There will be no further comment until a new head coach appointment is made." Chelsea invested a one-window Premier League record £273m to revamp Tuchel's squad this summer, bringing in Wesley Fofana, Kalidou Koulibaly, Marc Cucarella and Pierre-Emerick Aubameyang. But Sky Sports News understands Chelsea have been considering this decision for some time and it is not a knee-jerk reaction to Tuesday's Champions League defeat to Dinamo Zagreb. The new ownership has had concerns for some time and has been looking at other options. Now they want a long-term appointment to move Chelsea forward. /IANS