The team to win about 40% of games? (5)
'the team' is the definition.
Both the definition and answer are singular nouns.
Maybe there's a link between them I don't understand?
'win about 40 of games?' is the wordplay.
'about' indicates putting letters inside.
'40 of games?' becomes 'ga' (I am not sure about this - if you are sure you should believe this answer much more).
'win' placed around 'ga' is 'WIGAN'.
'to' is the link.
Can you help me to learn more?
(Other definitions for wigan that I've seen before include "The Road to -- Pier (Orwell)", "Manchester-area town, its Pier, Orwell", "Greater Manchester town with an "Athletic" football club", "North-western town", "Lancashire FC".)