Cheat pierces horse left in misery (11)

I believe the answer is:

hornswoggle

I'm a little stuck... Click here to teach me more about this clue!

'cheat' is the definition.
(I know that hornswoggle is a type of cheat)

'pierces horse left in misery' is the wordplay.
'pierces' becomes 'horns' (horning is a kind of piercing).
'horse left' becomes 'ggl' (I can't justify this - if you can you should give a lot more credence to this answer).
'in' means one lot of letters goes inside another.
'misery' becomes 'woe' (woe is a kind of misery).
'ggl' put within 'woe' is 'woggle'.
'horns'+'woggle'='HORNSWOGGLE'

Can you help me to learn more?

(Another definition for hornswoggle that I've seen is " bamboozle".)

I've seen this clue in the Sydney Morning Herald.

Want a hint initially instead of a full solution? Install my app