A race, I see, at a high level (5)
I believe the answer is:
attic
'high level' is the definition.
'attic' can be an answer for 'level' (I have seen 'Top level' mean 'attic' so perhaps 'level' could also mean 'attic'). I also know that 'high' relates to this answer.
'a race i see at a' is the wordplay.
'a race' becomes 'tt'.
'see' becomes 'c' (the word for the letter, according to Chambers).
'at' says to put letters next to each other (I've seen this in other clues).
'tt'+'i'+'c'='ttic'
'ttic' after 'a' is 'ATTIC'.
(Other definitions for attic that I've seen before include "Greek - garret" , "Top apartment" , "Of Athens" , "Dusty room" , "cockloft" .)