Top performers, some Adonis outrivalled, flipped (8)
I believe the answer is:
virtuosi
'top performers' is the definition.
(plural of virtuoso, term for a talented musician)
'some adonis outrivalled flipped' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'flipped' says the letters should be written in reverse.
'isoutriv' can be found hidden inside 'adonis outrivalled'.
'isoutriv' back-to-front is 'VIRTUOSI'.
(Other definitions for virtuosi that I've seen before include "Skilled musicians" , "Top players" .)