Anyone who could fight in the 100 degree July heat for 2-plus hours against Jake Kilrain with BAREKNUCKLES is a bad, bad man. The fact that he did this drunk is even MORE impressive. There's a reason the word "legend" is used when speaking of Sullivan.
Joe Mesi has always impressed me. . .. and with his superior strength (plus 100 years of technology in his favor, making workouts far more effective). . . . he'd give Sully a good scrap. But in the end, it just comes down to brute toughness.
Sullivan used acidic linaments on his face at night to "toughen his hide". . . in an attempt to avoid cutting. Today's fighters try their best to stay pretty, so they use Vaseline to make punches "slip away". . . also to prevent cutting and injury.
Back then, rounds weren't three minutes like today. . . rounds were over at a knockdown. . . . ten seconds or ten minutes. . whenever the knockdown came.
Overall, Sullivan defined "manliness" during a time when being a "gentleman" was the in thing. With a shot of whiskey and Cuban cigar never out of arm's reach. Sullivan with a twenty-round stoppage over a game but overmatched Mesi.