Diamonds taking off after slow start in sport (10)

'after slow start in sport' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'diamonds taking' is the wordplay.
I cannot quite see how this works, but
'diamonds' could be 'ice' (slang term for diamonds) and 'ice' is located in the answer.
an anagram of 'taking' is 'kating' which is located in the answer.
A single letter 's' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

'off' acts as a link.

Can you help me to learn more?