Better than the rest (4)
'better than the rest' is the definition.
This is all the clue.
(Other definitions for best that I've seen before include "Beat" , "Overcome" , "Of the highest quality" , "Superlative" , "or just the opposite?" .)
(Other definitions for second to none that I've seen before include "unbeatable" , "Outstanding" , "certain champion" , "Woodwind instrument" , "Pre-eminent" .)