What finally did in the Utes was not, as had been fantasized by more than one of its opponents, a stake through the heart, but, rather, a defense named after a microscopic organism.

When the University of Nevada-Las Vegas went to its "amoeba" zone defense in the second half of Thursday night's NCAA tournament game in the Kingdome, Utah's offense stagnated, its turnover rate increased and the Runnin' Rebels were at last and finally able to lose the Utes and vault themselves, by an 83-66 score, into the round of eight. The consolation for the Utes, who finished their most improbable season with a school-record 30-4 record, was that it wasn't an easy win, and certainly not manly, for a team many are calling the best in collegiate history.At halftime the Rebels were up by a mere six points, 41-35, despite shooting 60 percent from the field. Maybe they had won 43 games in a row. Maybe their average margin of victory this season was 29 points. Maybe they were 20-point favorites. But sitting there in their Kingdome locker room, they had to be wondering who were these guys from Utah?

Not unlike most every other team that had played the Utes this season - the most unassuming-looking 30-win team in the history of basketball.

Utah had only shot 43.8 percent in the opening half. If the Utes had made a couple of shots that had obviously been the result of first-half jitters, the game would have been even. In turnovers, Utah had seven at halftime, UNLV six. Rebounds were dead even, 15-15.

UNLV was feeling the heat. The Rebs were unable to rattle the Utes on offense with their pride-and-joy - a macho, don't-give-an-inch, we're-better-than-you-are, man-to-boy defense that has more or less made them the feared force they have come to be.

So they switched to the amoeba.

The amoeba is a zone defense invented in the Pittsburgh area in the early '60s. It became something of a regional sensation, which is how Tim Grgurich, a UNLV assistant who worked at Pittsburgh for 16 seasons before coming to Las Vegas, learned about its intricacies. He taught it to UNLV Coach Jerry Tarkanian.

The amoeba is so named because when properly executed it performs like amoebas perform in films you may or may not have watched in biology class. It's kind of a swarming, undefinable mass, with the lead part of it reacting to stimuli.

In basketball terms, that means that four members of the defensive team play a floating zone, and the player nearest the ball plays man defense.

When it works right, the offense is forced to spread out on the court like a patchwork quilt - in an effort to escape from the clutches of the amoeba - and open passes, and shots, become hard to come by. The theory is: You can run but you can't hide from an amoeba zone.

The weaknesses of the amoeba show up if an offensive team is exceptionally quick or exceptionally strong inside - two weaknesses that showed up last week when UNLV was scared into an eight-point win against Georgetown.

But the Utes, tired and somewhat worn in the second half, weren't able to expoit the amoeba's weaknesses. They went down like they'd been bitten by a bug.

Said Tarkanian, "They'd been attacking our man (defense) well. They were coming off screens real well and getting behind us. We were sliding on the floor, and that didn't help. It was the same floor for both of us, but we were playing pressure (man) defense, and they were playing position defense.

"When we went to our amoeba they had a difficult time with it. It worked surprisingly well."

Tarkanian said this with his eyebrows raised. Clearly, he didn't expect to be in a position of tinkering with his race car halfway through the race.

"I was so confident we could take them out of their offense (with man-to-man defense) and get them into freelance," he said. "But we couldn't."

Utah's Rick Majerus, a coaches' coach to the end, applauded Tarkanian in the manner of, say, a Kasparov applauding a Karpov.

"He made a great coaching move when he went to that zone," said Majerus. "We didn't expect that. We practiced our offense for their press. But not against that. We hadn't seen a zone for two or three months.

"It's an interesting zone," he continued. "They take so many chances with it. They get out of the passing lanes. They don't do the conventional slides. They're able to do that because of their quickness. They make good reads, and they make good decisions."

None better, as it turned out, than the decision to stop trying to slug it out with the Utes, man to man.

In the end, as Utah concludes a season where nothing happened the way it was supposed to, the Utes were done in by an ugly little swarm without a distinctive shape. They finally got stopped, but it took germ warfare to do it.