Was it the wide anticipation of a No. 1 ranking? The “white out” curse? Or maybe just some really bad early defense?

Opinions vary. But, ultimately, Arizona’s issues didn’t matter Saturday.

Bottom line: The Wildcats are now likely to become the nation’s top-ranked team for the first time in over a decade after surviving a scare from unranked UNLV and beating the Rebels 63-58 thanks to point guard T.J. McConnell’s heroics down the stretch.

Arizona is now 9-0, with a signature win over Duke, as well as a road win against San Diego State and few signs of weaknesses in its other games.

“It’s something we feel like we’ve earned,” UA coach Sean Miller said. “We know that being ranked No. 1 doesn’t mean we won a championship, or that the season’s now over. But I’m not going to play the negative card at all with that. I think it reflects the quality of our program, the incredible atmosphere that we have at McKale, the great teams in the past and certainly this year’s team.

“To be ranked No. 1 is maybe the greatest compliment that you can have.”

But, even after top-ranked Michigan State opened the door to No. 1 by losing to North Carolina on Wednesday, the second-ranked Wildcats almost knocked themselves out of consideration Saturday.

Arizona allowed UNLV to shoot 64 percent in the first half and never put the Rebels away even though UNLV has suffered three tough homecourt losses already while struggling to mesh a talented roster flush with transfers.

Several problems, on top of UNLV’s early shooting, made things notably worse for Arizona.

The Wildcats made only 3 of 16 three-pointers, with Nick Johnson going 2 for 9. They were essentially playing without one of their best shooters, Gabe York, who was yanked out of the game for good after six first-half minutes because of what Miller said were some early defensive mistakes.

Meanwhile, freshman forward Aaron Gordon struggled to shoot 2 of 10 from the field, and missed several minutes in the second half with a gash near his left eye.

Result: The lead changed 18 times and neither team led by more than six points.

For the Wildcats, it was scary.

“It shows us we can’t take a team lightly,” McConnell said. “UNLV is a great team who’s very well-coached, and they came in here and played really well and almost came out with a victory. We have to take each game like we’re playing Duke.”

So it was a letdown?

Um, not really, Miller said.

“It wasn’t about our team being tight or not playing hard defensively, or any of that — lack of effort, concentration,” Miller said, repeatedly praising UNLV and later adding: “We might have gambled a couple of times but it wasn’t a lack of effort or concentration.”

Well, then. How about that “white out” weirdness?

Arizona entered Saturday 1-2 in games when it asks its fans to wear white clothing, and Miller suggested after UA lost to UCLA last season that the promotion might be due for an early retirement. No doubt the promo would have been retired had UA lost Saturday.

Maybe it helped that not everybody was clued in to this phenomenon. Freshman forward Rondae Hollis-Jefferson said the Wildcats weren’t worried about what type of atmosphere there was and only that he noticed it was a “little brighter” out there with the added white.

What the Wildcats did notice: That UNLV was never going away.

The Wildcats trailed 42-39 at halftime, then watched their quick 6-0 run to start the second half get washed quickly away. UNLV took a three-point lead less than five minutes into the second half and later overcame another three-point UA lead to go ahead.

Part of the problem was that not long after Gordon dunked to give UA a 52-49 lead with 12:05 left, he took an inadvertent elbow near his left eye from Brandon Ashley.

“There was no question he took a pretty good shot,” Miller said.

Quickly, Gordon became a boxer between rounds, sitting on the bench while trainer Justin Kokoskie wiped away blood and had him hold an icepack. According to Miller, Gordon said he was OK, and so did Kokoskie, but the coach said he worried Gordon wouldn’t be himself when he returned to the game.

“But he’s a warrior,” Miller said, adding that Gordon will probably need a couple of stitches. “He’s one of a number of guys who maybe didn’t have as good an offensive night as he usually does but this was a high-level game and it was great for him to get back out there and fight.”

Gordon wound up logging 31 minutes, which was actually on the low side for a team that essentially used just six players, with York benched for the second half and Jordin Mayes making just a brief three-minute appearance after halftime.

That meant McConnell played 35 minutes and, not surprisingly, filled UA’s box score as a result. McConnell had 13 points, seven rebounds, six assists, three steals and only one turnover.

More critically, McConnell almost singlehandedly engineered UA’s stretch run, either making or assisting on the final five baskets, while also making 1 of 2 free throws with 15 seconds left.

Just 50 seconds after Hollis-Jefferson assisted McConnell on a midrange jumper that gave UA the lead for good, 58-57, with 3:10 left, McConnell found Hollis-Jefferson driving the baseline, and Hollis-Jefferson took it in for a dunk.

Hollis-Jefferson joked that he and McConnell have the “Pa. connection,” with them coming from opposite sides of Pennsylvania, and the two actually wound up tied for the team high in assists with six each.

“I like to find the open guy and get my teammates involved. That’s what I like to do,” Hollis-Jefferson said. “It feels great to do that.”

Hollis-Jefferson’s dunk put UA up by three points with 2:20 left, and after UNLV’s Khem Birch hit a free throw with 1:58, the Rebels did not score again.

Instead, McConnell dished it from the baseline to Ashley who drove straight in for a layup with 27 seconds left. McConnell later made a free throw for the final 63-58 score.

“I just tried to slow the game down and when I saw a shot or an open lane, I took it,” McConnell said. “When I saw someone open, like Rondae on the back-cut and when Brandon was driving baseline … credit to them because they finished those off and those are two big buckets.

“I think we all just let the game come to us, and I’m really glad we pulled this one out.”