Elicit cheers, as might a 2 1? (5,3,5,4)
I believe the answer is:
bring the house down
'elicit cheers' is the definition.
(to elicit a great audience reaction)
'as might a 2 1?' is the wordplay.
I cannot quite understand how this works, but
'as' could be 'in' (I've seen this in other clues) and 'in' is found within the answer.
This explanation may well be incorrect...
(Other definitions for bring the house down that I've seen before include "Enjoy great success" , "make people roar with laughter" , "Use a demolition ball" , "Demolition men may" , "evoke wild applause?" .)