Show confusion as small club's getting to grips with Arsenal at last (8)
I believe the answer is:
splutter
'show confusion' is the definition.
(I've seen this in another clue)
'small club's getting to grips with arsenal at last' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'club' becomes 'putter' (a golf club).
'getting to grips with' means one lot of letters goes inside another (one group of letters grips another).
'at last' indicates one should take the final letters.
The last letter of 'arsenal' is 'l'.
'putter' enclosing 'l' is 'plutter'.
's'+'plutter'='SPLUTTER'
'as' is the link.
(Other definitions for splutter that I've seen before include "Articulate confusedly, as in a rage" , "Throw out droplets or sparks" , "Eject drops" , "Make spitting sounds when speaking (in a rage?)" , "Talk incoherently" .)