Gary Cahill has revealed the drill Maurizio Sarri forced his players to do in training before every match at Chelsea.
The former Blues captain claims Sarri was 'very superstitious' and that his insistence on practising the same routine 'blew his mind'.
Sarri managed Chelsea for the 2018-19 season, leading them to third in the Premier League and lifting the Europa League with a 4-1 win over Arsenal before leaving for Juventus.
In his final season with the club and suffering from persistent injuries, Cahill saw his involvement slashed to eight games and was rather mocking of 'boring' Sarri in a chat with John Obi Mikel's 'One One' podcast.
'It was all just tactical. What is Sarriball? I played it and I still don't know what it is mate! But he didn't play me so...'
'It was very stand still. He was a very superstitious manager, very different.
'We used to do the centre (kick), set it back to one of the centre-backs, put a foot on it, and you used to just smash it diagonally, like the restart of a game. But you'd work on that every Friday with full international players.
'That only needs one session, doesn't it? If it's me and you, and you've got to put your foot on the ball, and I've got to smash it diagonally, that's all we need, one session.
'So that was the thing with the superstition, like every Friday or every day before a game, he'd practise it.
'It just blew my mind - I was thinking, it's alright the first few weeks when it's fresh, a few months in it's like, what's happening here? Do we need to do this again?'
Asked if the drill produced any gains, he replied: 'A few throw-ins I think if you overcooked it!'
Despite returning them to the Champions League and lifting a trophy, Sarri was never hugely popular at Chelsea.
Coming off the back of a transformative stint at Napoli, there was a general feel that he never quite got across his ideas - as demonstrated by Cahill claiming he still does not know what 'Sarriball' is.
It did not help that much of his communication came through a translator.
Cahill, who played eight times in his last season, said Sarri was a 'very superstitious' manager
His reputation in Italy was undimmed and the Italian giant agreed a £7million compensation deal with Chelsea to prise him away two years before the end of his contract.
However, despite winning the Serie A title in 2019-20, he was sacked by Juventus after being knocked out of the Champions League last 16 by Lyon, a tie which was finished in August due to Covid-19 delays.