Scottish town into Sunday racing (3)
I believe the answer is:
ayr
'scottish town' is the definition.
(I've seen this before)
'into sunday racing' is the wordplay.
'into' says the answer is hidden in the clue.
'AYR' is hidden in the letters of 'sunday racing'.
(Other definitions for ayr that I've seen before include "Scots port on Firth of Clyde" , "Scottish town, port and racecourse" , "Scottish city" , "Race course" , "Scots. town; sounds like song" .)