Means to level ground of latest against being included (5,5)

'means to level ground' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.

'of latest against being included' is the wordplay.
I cannot quite understand how this works, but
'of' could be 'o' and 'o' is found within the answer.
'against' could be 'on' (I've seen this in other clues) and 'on' is found in the answer.
an anagram of 'latest' is 'latste' which is within the remaining letters.
A single letter 'f' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?