One of the upper class? He's brought in for start of race (3,3)

'one' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'the upper class? he's brought in for start of race' is the wordplay.
I cannot quite see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within the answer.
'start' could be 'off' (as in 'from the off') and 'off' is found in the answer.
'he' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).

'of' is the link.

Can you help me to learn more?