Monitor top six side I'd ignored (9)
I believe the answer is:
supervise
'monitor' is the definition.
(I know that monitor can be written as supervise)
'top six side i'd ignored' is the wordplay.
'top' becomes 'super' (I've seen this before).
'six' becomes 'VI' (Roman numerals).
'ignored' is a deletion indicator.
'side' with 'id' taken out is 'se'.
'super'+'vi'+'se'='SUPERVISE'
(Other definitions for supervise that I've seen before include "Oversee, superintend" , "Oversee, monitor" .)