Fortunate even then as spoilt (6-4)
I believe the answer is:
heaven-sent
'fortunate' is the definition.
('heaven-sent' can be similar in meaning to 'fortunate')
'even then as spoilt' is the wordplay.
'spoilt' indicates an anagram.
'even'+'then'+'as'='eventhenas'
'eventhenas' anagrammed gives 'HEAVEN-SENT'.
(Other definitions for heaven-sent that I've seen before include "Very timely" , "Coming at a very opportune time" , "Occurring just at the right time" , "Providential" .)