Gain a best finish when put in skipping diversion (10)
I believe the answer is:
attainment
'gain' is the definition.
(thesaurus)
'a best finish when put in skipping diversion' is the wordplay.
I cannot really understand how this works, but
'a' is within the answer.
'best' could be 'ai' (resembles 'A1', old-fashioned term for excellent) and 'ai' is located in the answer.
'when' could be 'e' (I've seen this in other clues) and 'e' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for attainment that I've seen before include "Skill, achievement" , "The achievement (of a goal)" , "Laudable exploit" , "Realisation" , "Feat achieved" .)