Compile scores, ending in arrogant colleague winning (5,2)

'compile scores ending in arrogant' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'colleague winning' is the wordplay.
I cannot quite understand how this works, but
'colleague' could be 'ally' (I've seen this in another clue) and 'ally' is found in the answer.
'winning' could be 'up' (I've seen this in other clues) and 'up' is found within the answer.
A single letter 't' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...

Can you help me to learn more?