Maples Pavilion has just one scoreboard, a dated model from the 1990s that hangs over midcourt and is inconvenient to view for anyone who isn’t seated in row 47 or above.

For the longest time Thursday night, Arizona guard Nick Johnson would stop and look up, as if searching for a star somewhere, unsure if the Wildcats led or trailed.

Once, Johnson did a double-take. It was 53-53 for what seemed forever. Was the scoreboard broken? Had the timekeeper dozed off?

In fact, it was 53-53 for four full minutes, until 2:36 remained.

It was as if time had been suspended as the sharks circled and Arizona’s No. 1 ranking and 20-game unbeaten streak was imperiled. Johnson had been contained by the Cardinal defense, limited to nine points, and he was doubly miffed because he had bricked three foul shots.

“I kept looking over at Coach,” Johnson said. “He gave the freedom to call my play a few times in a row.”

On a night the Wildcats were uncharacteristically skittish offensively, and their vulnerabilities exposed, all it took was two shots to shake up the scoreboard and beat Stanford.

Johnson hit a floater in the lane before the scoreboard lights were permanently burned at 53-53 and then further jolted the Cardinal with a three-pointer in a game that exuded trouble from the opening tip.

Arizona won 60-57, and when Johnson had showered and dressed, he still dabbed at some sweat on his forehead.

“Ohhhh,” he said.

It was an “ohhhh” kind of game.

It doesn’t take much to lose a road game in the Pac-12, or anywhere, and Wednesday’s game was the kind of heart-burning experience that is likely to be repeated Saturday at Cal and in five more conference roadies.

But when you have a game-changer like Johnson,

it’s like you have an instant

Alka-Seltzer, on call, making

it all feel good in the end.

With 11:40 remaining Wednesday, Stanford led 51-47, and all the numbers suggested that Stanford would supplant Arizona as the No. 1 story on

the late-night edition of “SportsCenter.”

The Cardinal was shooting .475 afield and had a 26-20 rebound edge, which defied the way Arizona had beaten Michigan, Duke and San Diego State.

That’s when the Stanford side of the scoreboard froze.

The Cardinal missed 13 of its next 14 shots. The spoiler alert that had Maples Pavilion in a frenzy was numbed.

Arizona grabbed 16 rebounds in the final 11 minutes and played such lock-down defense that Stanford’s Josh Huestis delivered his team’s basketball obituary, saying, “In that stretch where we made one field goal, we let them move us off where we wanted to go. … That messed us up.”

Arizona did something remarkably similar in the final 12 minutes against Utah on Sunday, limiting the Utes to two field goals in that stretch. There’s winning with defense and then there’s REALLY winning with defense, and the Wildcats have now done it twice in four days.

UA coach Sean Miller said the game changed because of “our ability to defend at a very high level. We got defensive stop after defensive stop,” he said.

He was unhappy at his club’s free-throw shooting (18 for 29) — who wouldn’t be? — but he has been around long enough to know that style points are meaningless away from McKale Center.

“When you win on the road,” he said, “you have to take it as it comes.”

There is almost sure to be a night over the next six Pac-12 road games when Arizona’s foul-shooting, or lack thereof, will lead to a defeat. And you can’t continue to be the nation’s No. 1 team by shooting 36 percent, home or road.

But the Wildcats haven’t succumbed in the pressure, at Michigan or at Maples or anywhere.

When Arizona won 19 consecutive games in the 1997-98 season, punching through the Pac-10 season with a 16-0 record, it lost in the most unexpected way to the most unexpected opponent.

USC, which was 9-19, beat the Wildcats that night 91-90 in overtime, when an unknown guy named Adam Spanich drilled a three-pointer at the buzzer in regulation, and then won the game with another buzzer-beater in overtime.

They were Spanich’s only baskets of the game.

Who knows what lurks on the road?

You count your blessings and move on. It’s no wonder a Pac-12 team has never gone 18-0 since the league expanded 36 years ago. There are too many Adam Spaniches out there, and too many places like Maples, where Stanford rose to the occasion for 29 minutes and then coughed up the lead, unable to finish the job.

The curiosity about Arizona continues to grow. When Miller arrived at Maples on Wednesday a film crew jumped in his path, back-pedaling, following him to the UA dressing room.

And although about 40 percent of those in the crowd of 7,233 were Arizona fans, it was a spectacle that comes with being ranked No. 1. Stanford hadn’t even sold out, not close, its rivalry game with Cal earlier this month, drawing only 4,234.

Maples was a fortress for much of the night; the first “over-rated!” chants came after the Cardinal took a 2-0 lead.

As it turned out, Arizona is not overrated, not even close. You don’t get to be 21-0 on some flukish hocus-pocus. You don’t hold Stanford to four points in the final 11:40 unless you are the real thing.

For now, Arizona is No. 1, and no team in America deserves it more.

Sports columnist for the Arizona Daily Star.