Quick break after kick-off involves Croatia’s top international – him? (7)

'international him?' is the definition.
The answer and definition are not the same part of speech.

'quick break after kick-off involves croatia's top' is the wordplay.
'quick break' becomes 'vac' (I've seen this before. I am not sure about the 'quick' bit.).
'after' says to put letters next to each other.
'kick-off' becomes 'ko'.
'top' says to take the initial letters (in a down clue, the first letter is top).
The first letters of 'involves croatias' is 'ic'.
'vac' after 'ko' is 'kovac'.
'kovac'+'ic'='KOVACIC'

Can you help me to learn more?