On the way, champion gets a shellfish (7)

'shellfish' is the definition.
Both the answer and definition are singular nouns.
Perhaps you can see an association between them that I can't see?

'on the way champion gets a' is the wordplay.
I cannot really see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
'way' could be 'e' (Compass direction - East) and 'e' is found within the answer.
'a' is within the answer.
This may be the basis of clue (or it may be nonsense).

Can you help me to learn more?