Ultimately had to show determination following total collapse (8)
I believe the answer is:
downfall
'collapse' is the definition.
(I've seen this before)
'ultimately had to show determination following total' is the wordplay.
'ultimately' indicates one should take the final letters.
'following total' becomes 'fall' (I can't justify this - if you can you should give a lot more credence to this answer).
The final letters of 'had to show determination' are 'down'.
'down'+'fall'='DOWNFALL'
Can you help me to learn more?
(Other definitions for downfall that I've seen before include "Cloudburst" , "burst of rain" , "Ruin; heavy shower" , "Comeuppance" , "Ruin, humiliation" .)