I rewatched it, and it's honestly not that bad.
Yeah, Justin was better by a wide margin, but it's not like Tony got burtally KO'd or tapped to strikes like a Jones vs Shogun or something, or looked totally helpless the entire time like in a Khabib fight.
First round, got outlanded, ate some shots. Second round, same, arguably edged it with the knockdown. Going into the third there were still hopes that he would outlast Gathje. It was then that the damage started accumulating and he got cut up pretty bad, but he was there until the 5th, which was the only true 10-8 round. He ate some extremely hard KO looking shots, but he didn't really get teed off on against the fence or something similar. Still pretty brutal, but not as bad as I remembered it.