Team, one from Madrid, of stars (8)
I believe the answer is:
sidereal
'of stars' is the definition.
(sidereal means relating to the stars)
'team one from madrid' is the wordplay.
'team' becomes 'side' (both can mean a sports team).
'one from madrid' becomes 'real' (I am not sure about this - if you are sure you should believe this answer much more).
'side'+'real'='SIDEREAL'
(Other definitions for sidereal that I've seen before include "Relating to the distant stars" , "Like stars" , "Realised (anag) -- relating to the stars" , "Of the stars or constellations" , "Of or measured by the stars" .)