Crossword Genius

One friend changed rules if bet covered modern sport (8,7)

Ross

I believe the answer is:

ultimate frisbee

I'm a little stuck... Click here to teach me more about this clue!

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

'friend changed rules if bet covered modern sport' is the wordplay.
I cannot really understand how this works, but
'friend' could be 'mate' (mate is a kind of friend) and 'mate' is found within the answer.
'if' is within the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.
Want a hint initially instead of a full solution? Install my app