New smart fuel provided by expert (9)
I believe the answer is:
Here is my best explanation:
'expert' is the definition.
(I've seen this before)
'new smart fuel provided by' is the wordplay.
'new' indicates anagramming the letters.
'provided by' says to put letters next to each other.
'smart' put after 'fuel' is 'fuelsmart'.
'fuelsmart' is an anagram of 'MASTERFUL'.