That's one team out of the way! (5)
I believe the answer is:
aside
'out of the way' is the definition.
(synonyms)
'that's one team' is the wordplay.
'that's one' becomes 'a' (a thing is one thing).
'team' becomes 'side' (both can mean a sports team).
'a'+'side'='ASIDE'
(Other definitions for aside that I've seen before include "Apart; incidental remark" , "Actor's covert line" , "Out of other people's hearing" , "Separately" , "Actors comment to his audience" .)