The machinery of menace ground to a halt last Saturday. Just like that, Mike Tyson's dangerous leer was wiped from his bloodied face. He wasn't so tough. He wasn't that tough. These things can be discovered very suddenly. You could almost hear the clanking in the desert air, the train cars piling into one another as this engine of fear was wrenched to a standstill.

An economic empire had been built on Tyson's ability to paralyze opponents as much with his dark stare as with his ripping uppercut. Four times since his release from prison in March 1995, he had immobilized a foe, the job done long before the two boxers entered. It was a little disappointing, of course, when a so-called heavyweight champion fainted at the whiff of a left hook, as Bruce Seldon did two months ago. Still, these bouts had a perverse entertainment value. They were no longer sport. They were a spectacle of humiliation. And the promoters, even the fighter himself, smirked over the disturbing secret of their box-office power. "Thirty million a whop," Tyson said smugly. To see a guy give up his manhood.

It was a hateful thing, but there was no stopping it. The heavyweights were lined up from here to there. Tyson, untested in these four fights, was nevertheless assigned the ability to destroy all comers. The quickness of his bouts guaranteed his invincibility. There was no question that Evander Holyfield, too, would be run over on Saturday at Tyson's home court casino, the MGM Grand in Las Vegas. Perhaps Holyfield's confidence would not be shattered, as the others' had been, but he was certain to be consumed by Tyson's terrible force.

In fact, various agencies had worked mightily to diminish their culpability in the event of the worst-case calamity. The Nevada State Athletic Commission forced Holyfield, who was once told that he had a heart condition, to go through a battery of medical exams. A pay-per-view retailer offered its customers a by-the-round price so that fans would not blame cable TV too much for another one-round blowout.

Holyfield, 34, though used up by years of hard fighting and only 4-3 in his last seven bouts, was nonetheless an overachiever who might endure just long enough to offer the fans a colorful palette of gore in the WBA title bout. Tyson, 30, apparently stronger and stronger as his comeback progressed, would cut through this man whom he had been picked to beat when this bout was scheduled to take place five years ago, then postponed by a training injury to Tyson and later canceled by Tyson's rape conviction. As late as the boxers' walk to the ring on Saturday night, there was nothing to make you feel that Holyfield could join Muhammad Ali as the only three-time world heavyweight champion. Holyfield sauntered in to a soft ballad, singing along quietly. Tyson, preceded by his professional yeller, Crocodile, arrived at a gallop. He gave the impression of barely controlled anger, a desire to hurt that had found a satisfying and legal venue.

Not even what had happened in Tokyo six years ago, when an out-of-shape Tyson succumbed to Buster Douglas, prepared you for what happened next. Douglas-Tyson, called one of the biggest upsets in sports history, Can always be explained away by Tyson's lack of conditioning and desire. In this bout he suffered no lapse of preparation, no diminished lust for violence.

Tyson and Holyfield met in the center of the ring at the opening bell and engaged in the kind of furious combat that no heavyweight fight fan had seen in years. They swung wildly and then collapsed into clinches, shoved each other away and finally resumed battle as the cycle began again. It was breathtaking, especially when it became clear that Holyfield would not be flattened by Tyson's straight-ahead fusillades. Suddenly Holyfield, the built-up cruiserweight, seemed formidable at 215 pounds, his 77½-inch reach putting him out of range of Tyson's 71 inches.

In the second round Holyfield, who is not known as a big puncher, hit Tyson with a left hand that seemed to stagger him. At the end of the round Tyson paused on his way to his corner and looked at Holyfield as if puzzled. In fact he was, as he admitted later, "blacked out." The fight went eight more rounds, until referee Mitch Halpern stopped it less than a minute into the 11th, but afterward Tyson could recall none of them. For everyone else the bout was unforgettable. Holyfield's constant pressure was a welcome sight after the weak-kneed efforts of Tyson's previous opponents, but the challenger was providing something more than action. By crowding in, he was taking away Tyson's hook, which is more effective from outside, and generally he was keeping Tyson too occupied to put together more than two punches.

Tyson was always a threat, of course, and in the fifth round he unleashed a right to Holyfield's body and an uppercut to his chin, reminding everyone of his power. But Tyson was plainly befuddled, strangely ineffective. The two fighters would clash, tie up and get broken apart by the referee, and there Holyfield would be, still standing in front of Tyson.

Later Tyson would say he remembered nothing from the third round on. Not the sixth round, when Holyfield opened a small cut above Tyson's left eye with an unintentional head butt and then decked him with a left hand as 16,325 people chanted Holyfield's name. Tyson was definitely in trouble. In the seventh he kept looking to Halpern, complaining about head-butting. And later in that round he rushed Holyfield face-first and inadvertently smashed his left eye into Holyfield's shaved head. Tyson gasped in pain, stood straight up and appealed to the ref again.