Bill upset club (3)
I believe the answer is:
Here is my best explanation:
'bill' is the definition.
(tab is a kind of bill)
'upset club' is the subsidiary indication.
'upset' says the letters should be written in reverse.
'club' becomes 'bat' (bat is a kind of club).
'bat' reversed gives 'tab'.
(Other definitions for tab that I've seen before include "Bill", "Tag", "The bill in a restaurant", "Running bar bill", "Bar tally; small flap", "Text indent key", "Tally at bar (colloq.)", "Marker", "Kind of label for bat" and "Ring pull".)