Shockingly, it went with the last century (9)
I believe the answer is:
'last century' is the definition.
(I've seen this before)
'shockingly it went with the' is the wordplay.
'shockingly' is an anagram indicator.
'with' is a charade indicator (letters next to each other).
'itwent' after 'the' is 'theitwent'.
'theitwent' is an anagram of 'TWENTIETH'.
(Other definitions for twentieth that I've seen before include "Ordinal number for this century" , "at the end of a score" , "Last century" .)