Great footballer, I see, is saviour (7)
I believe the answer is:
messiah
'is saviour' is the definition.
(I've seen this before)
'great footballer i see' is the wordplay.
'great footballer' becomes 'messi' (footballer Lionel Messi. I am not sure about the 'great' bit.).
'i see' becomes 'ah' ('ah' can be used to express understanding).
'messi'+'ah'='MESSIAH'
Can you help me to learn more?
(Other definitions for messiah that I've seen before include "well-loved music" , "A hoped-for saviour" , "The Promised One" , "Leader, saviour" , "His coming was prophesied in the Old Testament" .)