Gianfranco Zola believes Chelsea loanee Nathaniel Chalobah can play at the highest level but has stressed the youngster needs to maintain his desire to improve if that is to happen.
Chalobah is just 17 years old but has been part of Chelsea's pre-season squad in the last two years and travelled with the team for their Champions League win in May.
The midfielder, who can also play in defence, is England Under-19 captain and impressed during his first professional start on Saturday, when Watford drew 2-2 with Bristol City.
Chalobah excelled in holding midfield during the first half and whilst he found it harder as part of a back three following the break, Chelsea legend Zola praised the rising star's performance.
Zola said: "I thought for 25 minutes, or 30 minutes, he was quite outstanding. His performance was really top class and he played well when he also went to the back.
"He is a player that if he maintains the right attitude and keeps working and focussing on learning then he could really become an important player."
The term highly-rated is often over-used but when it comes to Chalobah that is not the case.
Chalobah, who was born in Sierra Leone, has played for older age groups for much of his life and captained not only the Chelsea Under-18s to FA Youth glory this year, but is England Under-19
skipper and also captained the Reserves on several occasions last season.
He signed his first professional contract, a two-and-a-half year deal, in January following his 17th birthday and has been an unused substitute in the past.
Zola knows a few things about playing at the highest level, and particularly for Chelsea, and when asked how far Chalobah can go, Zola replied: "He can go as high as he wants to.
"He has all the qualities to become a top player but he just needs to work hard every day and not lose the desire to work hard in training.
"The common mistake for players of his age, when they play and are having compliments like I am giving him right now, is to stop learning.
"It is too early; he has the potential but he has to really keep his feet on the ground and work hard."