I agree he was getting tired he after all went 12 hard rounds with Rocky but the 13th had just started and he was doing OK keeping the range where he wanted turning him and trying to walk him in to punches like he did in the 1st with the hook juking and jiving typical Walcott style. I am not suggesting that the fight wasn't tough or competitive Walcott was winning and dishing out alot of punishment as well receiving some, Walcott was no powder puff puncher he had good power but his style was his niche.
Whatever we call it, it was a great victory. Marciano, the novice, took the old pro into deep waters and drowned him. It didn't come out of the blue but it was a conclusive victory.
It was like a man who lived a long and productive life who crossed the street one day and got hit by a truck.
With several cuts on his face, a problem with his vision from the 6th round after a clash of heads had both men bleeding ,his manager , as much use in a corner as a chocolate mouse at the best of times,and a hysterical liability in this the most important fight of Rocky's career , after being comprehensively out boxed in a lot of rounds ,trailing on the scorecards, Marciano showed a champions heart and an indomitable will to win. The guy just could not be discouraged, people talk about him breaking blood vessels , well he must have broke a few fighters hearts too. Marciano turned pro late, short of stature, reach , not gifted with great boxing skills,comparatively slow afoot, but coupled with power , he brought an unbelievable level of conditioning into the ring and an iron mind set that refused to be defeated. A hundred and eighty seven pounds , at least half of which was heart. The bench mark over achiever.
But then nor does any knock out in a boxing ring. It was a very sudden knock out. A one punch knockout.
It shouldn't have been unexpected to the educated observer. Much like Taylor getting stopped by Chavez wasn't a surprise to me as the rounds went by. Again, Marciano almost traps Walcott in the same position several times before... and in fact lands his right a couple times, but Walcott is still too elusive, too quick, too slippery. Marciano slowed him down by administering punishment and surviving Walcott's great exertion.
It was sudden. Obviously any time a puncher like Marciano (or Walcott, for that matter, and many other HWs) gets in the ring a KO isn't completely unexpected. I can't say I've ever heard anyone who saw it live say they sensed that Marciano was going to do that though.