Expect ticket – using theatre for play's opening (5,2)
I believe the answer is:
count on
'expect' is the definition.
(thesaurus)
'ticket using theatre for play's opening' is the wordplay.
I cannot quite see how this works, but
'using' could be 'on' (someone using drugs is 'on' them) and 'on' is found within the answer.
'theatre' could be 'nt' (National Theatre) and 'nt' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for count on that I've seen before include "Rely upon" , "Put one's trust in" , "Judge to be probable" .)