Marco Silva has told Everton's official website that Michael Keane is a different player now to the one he inherited during the summer.
The 25-year-old has been a rock for Everton this season, starting nine Premier League games and scoring once.
His good form was rewarded by Gareth Southgate in midweek when the England boss handed him a recall to the international scene for the first time in a year.
Keane endured a tough first season at Goodison Park last term following a £30 million move from Burnley, struggling for form under Ronald Koeman and later Sam Allardyce.
But Silva claims that the Manchester United youth has been transformed since he has taken the reins on Merseyside.
He told Everton's official website: “Last season wasn’t easy for him, coming to a new club and trying to have an impact, but I see a big difference in him now. I realised when I started to work with him during pre-season that his confidence was not high.
“But we saw in him the qualities to be one of our central defenders. We worked with him and believed in him in that moment because we saw his qualities as a central defender.
“He is improving and understanding our model and trying to do everything we ask from him. And he is performing well because he has the skills to do that."
Keane does look a better, more confident defender this season - but Sunday is a huge test.
Silva's side take on Chelsea at Stamford Bridge, and if Keane can maintain this purple patch then it'll go a long way toward convincing Everton fans that he is indeed a changed man.