Person offering testimonial for match official (7)
I believe the answer is:
referee
This clue is a double definition.
'person offering testimonial' is the first definition.
'match official' is the second definition.
(I've seen this before)
'for' acts as a link.
(Other definitions for referee that I've seen before include "Sports official" , "Football official" , "Sports adjudicator" , "Umpire; arbitrator" , "Match official" .)