Accepted statement from a football team over millions (5)
I believe the answer is:
axiom
'accepted statement' is the definition.
(an accepted belief or idea)
'a football team over millions' is the wordplay.
'football team' becomes 'XI' (a football team, from Roman numerals for 11).
'over' becomes 'o' (cricket abbreviation).
'millions' becomes 'm' (abbreviation).
'a'+'xi'+'o'+'m'='AXIOM'
'from' acts as a link.
(Other definitions for axiom that I've seen before include "Statement regarded as self-evidently true" , "Principle; assumption" , "Maxim - truism" , "Acceptable principle" , "Self-evident statement" .)