One commanding batsman going up over mid-off (7)
I believe the answer is:
admiral
'one commanding batsman going' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'up over mid-off' is the wordplay.
'up' becomes 'aral' (I can't explain this - if you can you should give a lot more credence to this answer).
'over' indicates putting letters inside.
'off' indicates anagramming the letters.
'mid' anagrammed gives 'dmi'.
'aral' enclosing 'dmi' is 'ADMIRAL'.
Can you help me to learn more?
(Other definitions for admiral that I've seen before include "High-ranking naval officer like Nelson" , "Chief commander of fleet" , "Senior officer; mad liar (anag.)" , "Highest naval rank" , "Navy chief" .)