It proved to be the decisive result for American owner Boehly who has ruthlessly relieved Tuchel of his duties after less than two years in charge.
The new ownership group splashed out eye-watering amounts of money during the transfer market, spending around NZ$514 million on nine signings.
After the nightmare defeat on the road, Tuchel unloaded on his playing group.
"I am angry with myself, I am angry about the performance.
"This is a huge underperformance from all of us. It's not precise enough, it's not clinical enough, not aggressive enough. It is not determined enough. It is not enough individually, it is not enough as a team and that is why we lose this game today."
But on Wednesday night his fate was sealed as the club sensationally cut ties with the German.
"Chelsea Football Club has today parted company with Head Coach Thomas Tuchel," a club statement read.
"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.
"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.
"There will be no further comment until a new head coach appointment is made."
The news of Tuchel's axing left the football world in utter disbelief.
Tuchel won the Champions League with Chelsea in his first season as well as claiming two minor trophies.
After being hired in January 2021, Tuchel, 49, guided Chelsea to the FA Cup final and EFL Cup final last season.
According to The Telegraph, Tuchel lost the faith of Boehly and his players. They state that his future at Chelsea would have been in doubt even if they had claimed three points against Zagreb.
It has been said that first team coach Anthony Barry will likely take charge on an interim basis for the meantime as Chelsea look for a new manager.
