Ace revealed when Pat has dealt cards (3,4)
I believe the answer is:
dab hand
'ace' is the definition.
Both the answer and definition are singular nouns.
Maybe they are linked in a way I don't understand?
'when pat has dealt cards' is the wordplay.
I cannot really see how this works, but
'pat' could be 'dab' (synonyms) and 'dab' is found in the answer.
'cards' could be 'hand' (I've seen this before) and 'hand' is found within the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'revealed' is the link.
Can you help me to learn more?
(Other definitions for dab hand that I've seen before include "Barely wash" , "An informal expert such as band had" , "Past master" , "cursory wash?" .)