Struggled with mat (3)
I believe the answer is:
rug
'mat' is the definition.
(floor covering)
'struggled with' is the wordplay.
'with' indicates a hidden word.
'RUG' can be found hidden inside 'struggled'.
(Other definitions for rug that I've seen before include "Small carpet" , "grace the boards" , "Mat or knee-cover" , "One covering" , "Thick floor-mat or coverlet" .)