Cesc Fabregas has been mightily impressed by the way former team-mate Frank Lampard has started his managerial career as talk of a Chelsea return continues.
Maurizio Sarri endured a topsy-turvy first season at the helm of the west London club, whom he led to the Carabao Cup final, a third-place finish in the Premier League and Europa League glory.
The Italian is now wanted by perennial Serie A champions Juventus, with Chelsea great Lampard the bookmakers' favourite to replace him should he leave.
The club's all-time top scorer led Derby to the Sky Bet Championship play-off final in his first season in management and, while they fell just short of promotion, former Blues midfielder Fabregas likes what he has seen.
"I think he has done a really impressive job," the Spaniard told Press Association Sport. "It's his first ever job. He changed many things.
"I saw him in Russia with the BBC (when working at the World Cup) and he had a very difficult squad, an older squad full of players at the end of their contracts as well.
"He renewed completely the squad, took on young players.
"He played a really aggressive style, attacking football. Really for a first ever job, I think he has done really good."
While Fabregas appreciates the work Lampard has done from afar, the midfielder has seen first-hand how Sarri operated at Chelsea.
The 32-year-old started the 2018-19 season with the Blues and moved to Monaco in January, having found opportunities hard to come by under the Italian.
"Well, he is a manager with his own ideas and he doesn't move from them much," Fabregas said of Sarri.
"He has an idea of how he wants to play and the football that he really wants to play. He doesn't move from it.
"No matter what you tell him, no matter what you advise him, no matter what your opinion is, he will never change.
"He is very superstitious, he is very stubborn in this way.
"But he did it the way he likes it. He has his own vision of football and, in the end, he is where he is with it and you have to respect that."