Gianfranco Zola has admitted that he did not expect Fikayo Tomori to become a first-team regular at Chelsea.
After spending a year in the Championship with Derby County, Tomori has established himself in the centre of Chelsea's backline, while also earning international recognition with England.
Zola worked on the backroom staff at the Blues last season, and the club legend has acknowledged that the academy graduate's progression has come as 'a big surprise'.
The Italian is quoted by the London Evening Standard as saying: "Last year we had him in the pre-season and we couldn't see all the qualities that he is showing now.
"That is a surprise and a big lesson for us and me personally as well. They are going beyond my expectations."
The 21-year-old has made 13 starts in all competitions during the current campaign.
