Haye is scared of looking average. He knows he either knocks Briggs out or gets criticism for not knocking out an older larger man. Only way Haye knocks out Briggs is if he's truly a dangerous contender of which he really isn't until he proves it.
Briggs has a strong chin, Vitali put him into the hospital, broke his nose, jaw, etc., the fight should have been stopped. Haye can beat Briggs, but he might not be able to knock him out, however, Vitali might have permanently damaged Briggs..................