Dancing duo to excel (5)
I believe the answer is:
outdo
'excel' is the definition.
(I've seen this before)
'dancing duo to' is the wordplay.
'dancing' indicates an anagram.
'duo'+'to'='duoto'
'duoto' is an anagram of 'OUTDO'.
(Other definitions for outdo that I've seen before include "Beat" , "Be better in performance (than another person)" , "Eclipse" , "Surpass - overshadow - excel" , "Overtake" .)