The guiding principle of playing the nation’s No. 1 basketball team is that you use all your ammo. You give it your best shot, and if that doesn’t work, you vow to get ’em the next time.

That’s what Utah did Sunday night at McKale. The Utes got an extra day of practice after losing Thursday at Arizona State and coach Larry Krystkowiak didn’t use it to get some sun.

“We used a triangle-and-two defense,” he said. “We used a bump zone. We used a switching zone.”

For 35 minutes, the Utes used everything but six men on defense. It was right out of the Book of Rich Majerus. Hit ’em with what they’ve never seen.

The Utes jumped to a 12-2 lead and Sean Miller said, “We kind of had that, ‘What do I do?’ look.”

It was a chess match and then some, multiplied by Utah’s hunger to beat the nation’s No. 1 team.

“They switched on every screen in man-to-man,” said Miller, who then listed a litany of defenses the Utes deployed to bewilder the Wildcats. “They did things they don’t necessarily do.”

It was, as Arizona guard Nick Johnson said, “the hardest 11-point win we’ve had.”

The Utes played so hard that even Johnson was confused. Arizona won by nine, 65-56, and the message Utah sent was received. This business of being No. 1 comes with a price.

Nobody’s going to step aside and admire your pose.

“We just know that every single game we’re going to get everybody’s best shot,” said Johnson, who in the last few weeks has shot onto everyone’s All-American team. “People make shots they don’t normally make against other teams.”

In the end, Krystkowiak left McKale feeling sick twice. Utah’s coach literally has some sort of winter gunk, and, to make it worse, his team only had 35 minutes of fuel before conking out, out-rebounded so thoroughly by Aaron Gordon and Rondae Hollis-Jefferson that it was easy to overlook how well the Utes played until then.

“They pounded us, pounded us,” said Krystkowiak. “We couldn’t match their physicality. I’d buy into the fact that maybe we gave into fatigue a little bit.”

He compared the Wildcats to a football team that runs the ball up the middle, “grinding you, grinding you,” and that was about the only way Arizona could’ve avoided a colossal upset Sunday.

Utah isn’t ranked and won’t be ranked this year, but it has improved so much over Coach K’s first three seasons that he should get strong Pac-12 Coach of the Year consideration.

When Arizona plays in Salt Lake City next month (and especially next year), it’s unlikely the Utes will use the “fatigue” card again. Jordan Loveridge and Delon Wright are outstanding; none of the Utes who played Sunday is a senior.

“Going on the road is going to be hard,” said Miller, “but when you’re No. 1 and you’re going on the road, I can make a case that it might even be harder.”

Arizona should enjoy being 20-0 for the next 72 hours because that’s about the time that hitting the road might hit back. If you think Sunday’s game was labor, Wednesday’s visit to the Sixth Man Club at Stanford and Saturday’s foray to the Straw Hat Band at Cal won’t be anywhere near as friendly as it was Sunday at McKale.

The Wildcats have been in danger before; they trailed Drexel 27-8 at Madison Square Garden. But this time, against Utah, it seemed more perilous.

Gordon had his worst shooting night (3 for 13) of the season, T. J. McConnell missed seven shots, and Kaleb Tarczewski was outscored by both Utah centers, Jeremy Olsen and Dallin Bachynski.

It’s not often you can overcome those variables, shooting 61 percent from the foul line and just 21 percent from three-point range.

You don’t have Gilbert Arenas or Salim Stoudamire to shoot you back into the game, so you do it the hard way. You beat ’em on the boards and play lock-down defense.

“That’s what we signed up for,” said Hollis-Jefferson. “To be warrior guys.’’

You continue to forge an identity as a defensive stopper, which requires size, toughness and willpower.

“Holding them to (56 points) is about as well as we could do defensively,” said Miller.

Except for Hollis-Jefferson, whose Chester, Pa., high school team went 34-0 when he was a junior, none of the seven Wildcats in Miller’s rotation knows what it’s like to be 20-0.

The other six rotation players have all been bumped off by a team like Utah in the middle of a championship-type season.

On the way to a 29-2 season, McConnell’s Chartiers Valley (Pa.) High School team was 14-0 when it was stunned by the Neumann-Goretti Saints in 2010. Brandon Ashley’s Findlay Prep (Nev.) team, which went 29-1, was upset by LaLumiere High of Indiana after opening with 12 straight wins.

And Tarczewski’s 28-2 St. Mark’s (Mass.) team was knocked off in midseason by the United Faith Christian Academy of Massachusetts.

Very few are perfect in this game. Arizona has survived, unscathed, for about as long as can be expected.

“Nobody’s interested in the song and dance of losing close games,” said Utah’s Krystkowiak.

So far, the Wildcats are still dancing, still singing the song of the nation’s No. 1 team.

Sports columnist for the Arizona Daily Star.