Ring for sporting combat, Tyson's oddly missing - work hard at the start (5)

'ring for sporting combat' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'tyson's oddly missing work hard at the start' is the wordplay.
'oddly missing' indicates alternate letters.
'work' becomes 'do' (synonyms).
'hard' becomes 'h' (abbreviation used in pencil classifications).
'at the start' is a charade indicator (letters next to each other).
The alternating letters of 'tyson' are 'yo'.
'do'+'h'='doh'
'yo' after 'doh' is 'DOHYO'.

Can you help me to learn more?