Start to triumph in element of Scrabble championship (5)
I believe the answer is:
title
'championship' is the definition.
('title' can be a synonym of 'championship')
'start to triumph in element of scrabble' is the wordplay.
'start to' suggests taking the first letters.
'in' means one lot of letters goes inside another.
'element of scrabble' becomes 'tile' (I can't justify this - if you can you should give a lot more credence to this answer).
The first letter of 'triumph' is 't'.
't' inserted into 'tile' is 'TITLE'.
Can you help me to learn more?
(Other definitions for title that I've seen before include "Identifying name" , "Handle" , "Name of film, book etc" , "Book's name" , "Name; heading" .)