Leader to lead with three articles (3,6)
I believe the answer is:
top banana
'leader' is the definition.
(I've seen this before)
'to lead with three articles' is the wordplay.
'three articles' can mean three substitutions for 'article'.
'lead' becomes 'pb' (Pb is the chemical symbol for lead).
'with' says to put letters next to each other.
'article' becomes 'an' (indefinite article).
'article' becomes 'an' (indefinite article).
'article' becomes 'a' (the indefinite article in English).
'to'+'pb'+'an'+'an'+'a'='TOP BANANA'
(Other definitions for top banana that I've seen before include "Big cheese" , "Star comedian" , "1" , "first on hand?" , "leader" .)