Close on two soccer teams departed after end of last year (6)
I believe the answer is:
'close on two soccer teams' is the definition.
(twenty is nearly twenty two)
'departed after end of last year' is the wordplay.
'departed' becomes 'went' (I've seen this before**).
'after' means one lot of letters go next to another.
'end of' suggests the final letters.
'year' becomes 'y'.
The last letter of 'last' is 't'.
'went' put after 't' is 'twent'.
(Other definitions for twenty that I've seen before include "No. between 5 and 1 on dartboard" , "Score, XX" , "Hundredweights to a ton" , "One score" , "Cardinal" .)