Spain's top footballer is one scoring openly (7)
I believe the answer is:
swinger
'one scoring openly' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'spain's top footballer' is the wordplay.
'top' indicates taking the first letters (in a down clue, the first letter is top).
'footballer' becomes 'winger' (winger is a type of footballer).
The first letter of 'spains' is 's'.
's'+'winger'='SWINGER'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for swinger that I've seen before include "Ball swerving in the air (cricket)" , "Lively guy" , "lively type" , "curving ball" , "one after the other" .)