Start to perform Evita badly (8)
I believe the answer is:
activate
'start' is the definition.
(I've seen this in another clue)
'perform evita badly' is the wordplay.
'perform' becomes 'act' (acting is a kind of performing).
'badly' is an anagram indicator.
'evita' with letters rearranged gives 'ivate'.
'act'+'ivate'='ACTIVATE'
'to' is the link.
(Other definitions for activate that I've seen before include "Start working" , "Put in motion" , "Stimulate to action" , "Set off, trip" , "Give life to" .)