Numbers left in games (8)
I believe the answer is:
twenties
'numbers' is the definition.
(twenty is a number)
'left in games' is the wordplay.
'left' becomes 'went' (left can mean went away).
'in' indicates putting letters inside.
'games' becomes 'ties' (tie can mean a sporting fixture).
'went' going into 'ties' is 'TWENTIES'.
(Other definitions for twenties that I've seen before include "First adult years" , "decade of frivolity" , "what lies ahead for 27 [TEENAGER]?" , "The decade was said to be roaring" , "ten years" .)