To have the nerve to (A), To have the gall to (A), To freaking (A)
Structure:
Verb［stem］+ やがる
Verb［て］+ やがる
Are the non JLPT grammar points provided on an “as is” basis? I’ve seen a couple solutions that I find frustrating, but this is one seems bordering on ‘impossible to know’.
コーチ：「あいつ、また格下の相手に負かされ____！」
With 「やがって」 being the answer. There seems to be absolutely no hint on the desired tone, te form, etc.