Personally, in my opinion (my opinion, not yours sorry) I think the man on the right will win because he can more easily show his cock to his opponent, which could give him an advantage as the opponent may hesitate to shoot when he sees the cock.

Also, the man on the right has full face protection, so it is likely that a shot to the face will not kill him instantly. Also, he can show his cock more easily.

Furthermore, the man on the right can more easily seduce the man on the left with his butthole which should be visible even though he is wearing underwear. This is because the thong is very far up between his butt cheek (kinda sexy, also he can easily show his cock). I think anal instead of battle is beneficial for everybody (and also sexy).

Thank you