Personal objective in move that backfired? (3,4)
I believe the answer is:
own goal
'move that backfired?' is the definition.
(goal scored against one's own team)
'personal objective' is the wordplay.
'personal' becomes 'own' (eg one's own possessions are personal possessions).
'objective' becomes 'goal' (goal can mean an objective or purpose).
'own'+'goal'='OWN GOAL'
'in' acts as a link.
(Other definitions for own goal that I've seen before include "Unfortunate football incident" , "A score against one's self or team" , "Have a target" , ""Wrong-net" score" , "Self-made disadvantage" .)