London: Chelsea started their league season with five successive victories and went unbeaten until late November. There was a lot of positive talk about the impact of Maurizio Sarri and how his successful style of football at previous club Napoli was being transferred so quickly to Chelsea. In these early weeks of the campaign Jorginho was dictating matches from a deep-lying midfield position while N’Golo Kante scored on the opening weekend appearing to relish a modified and less defensive role.

Some cracks are starting to show and they seem to be spreading quickly. It certainly looks like Sarri’s honeymoon is now over.

Performances have gone downhill, with Saturday’s 2-0 defeat at Arsenal their fourth in 11 league games and widely considered a new low. But what was surprising to me was what Sarri had to say afterwards: criticising his players’ “mental approach”, saying Arsenal were “far more determined than we were” and most eye-catchingly suggesting Chelsea’s squad is “extremely difficult to motivate”.

More recently Sarri made it clear that he had said something similar in the dressing room. “Why keep it a secret?” he asked. “I want to be direct with them in private and in public.” But this is always dangerous ground for a coach to tread, especially so early in his tenure.

Public criticism of players can go one of two ways: either the players will want to prove their manager wrong, or the squad will go within themselves and performances will deteriorate. If a manager wants to get a reaction, they are better off speaking to players privately.

What we’ve seen in the recent past is that public criticism of players just doesn’t work. Think of Marcus Rashford, Luke Shaw and Paul Pogba at Manchester United under Jose Mourinho. Players are under enough pressure to perform from fans and the media, without a manager complicating matters further in public. Top players will not let it affect them too much but it is not something they appreciate.

After all, Alex Ferguson, one of the greatest managers of all time, had a golden rule never to criticise his players in public despite being famously known to give “hairdryer treatments” in private. This approach, in protecting his players publicly, clearly worked for Ferguson and brought him unprecedented success and loyalty of his players.

Sarri must tread very carefully or it might end as badly for him as it did for his predecessors at Stamford Bridge — Mourinho and Antonio Conte. And both Mourinho and Conte had won the league title before their relationship with the players started to slide.