Gianfranco Zola believes Maurizio Sarri left Chelsea too early.
Sarri asked to go after just one year to return home to Italy and become Juventus boss paving the way for club legend Frank Lampard to replace him as head coach.
Sarri’s Chelsea No 2 Zola, who followed his countryman out of Stamford Bridge, said: ‘I think the best of Maurizio’s work comes not in the first year but more from the second year onwards.
‘Looking at the way he works, it takes a little bit of time to put in place what he wants to do and also he is very demanding on the players.
‘But, after the players get used to it, they get better and better and the work becomes more effective.
‘It’s a pity, because I think it would have been good for the club if Maurizio stayed and it would have been good for Maurizio as well.’
Lampard gets his Chelsea reign underway with Wednesday’s friendly against Bohemians.
He now has 34 players to run the rule over after 13 more joined his squad in Ireland including Kepa, David Luiz, N’Golo Kante, new permanent signing Mateo Kovacic and Olivier Giroud.
Academy duo Mason Mount and Tammy Abraham have also linked up after successful loan spells in the Championship last season.