Ignatius, apt to fail in difficulties (2,7,2)
I believe the answer is:
up against it
'in difficulties' is the definition.
(I've seen this before)
'ignatius apt to fail' is the wordplay.
'to fail' is an anagram indicator (letters go wrong or fail).
'ignatius'+'apt'='ignatiusapt'
'ignatiusapt' with letters rearranged gives 'UP AGAINST IT'.
(Other definitions for up against it that I've seen before include "in dire straits" , "Harried" , "In near desperate straits" , "Keep in custody" , "Experiencing difficulties ?- it???'s a gut pain! (anag)" .)