Be enough for holding popular strike (3,4)
I believe the answer is:
run into
'strike' is the definition.
(I know that strike can be written as run into)
'be enough for holding popular' is the wordplay.
'be enough for' becomes 'run to' (run to can mean to be sufficient for).
'holding' indicates putting letters inside.
'popular' becomes 'in' ('in' can mean trendy).
'runto' placed around 'in' is 'RUN INTO'.
(Other definitions for run into that I've seen before include "Happen to meet or collide with" , "Encounter by chance - or collision?" , "'Meet by chance (3,4)'" , "Meet (someone) unexpectedly" , "Meet accidentally on the trot?" .)