No. 1 Arizona heads into the Christmas break with a perfect record, but after an undefeated nonconference run last season coach Sean Miller offered an almost spooky premonition.

“You worry sometimes about how many points you are scoring, how you are playing individually as opposed to what’s happening as a team,” he said last season just before the Wildcats began Pac-12 play at 12-0. “Sometimes guys can really get caught up in their own world. … The longer a season goes on, the more team dynamics become a factor.

“I’m only bringing that up because that’s a real focus for us moving forward.”

Two days after Miller offered those words, host Arizona needed a controversial wave-off of a Colorado buzzer shot to escape the Buffaloes in overtime. Then the Wildcats beat lowly Utah by only three points.

And the next week, Arizona went to Oregon and allowed the Ducks to shoot 56.7 percent in the first half, leading to UA’s first loss of the season. There were five more losses, costing them a chance to win the Pac-12 regular-season title.

All that after UA merrily hopped a Christmas night red-eye flight from Honolulu to Phoenix, having won the Diamond Head Classic, then took a few days off.

“When we got back, we lost our defense,” Miller said. “Our defense a year ago was very good. It wasn’t as good as this year’s defense. But we went through a four- to five-week period of time when we got back from Christmas where we didn’t play nearly tough enough defense to be the Pac-12 regular-season champions.”

Arizona held opponents to 38.9 percent shooting during the 2012-13 nonconference season but Colorado shot 47.5 percent, even better if Sabatino Chen’s would-be buzzer-beater was not called off. Utah shot 42.9 percent. Oregon hit 7 of 11 three-point attempts. And UCLA, while beating up the Wildcats during a “white-out” game at McKale Center, shot 47.8 percent.

Something was wrong. Miller explained what it was after UA beat NAU 77-44 on Monday to complete another undefeated nonconference run.

“One of the things I learned as a coach last year is when you have selfishness, any chemistry breaks from your team, or one player gets off on a different page, the first thing that goes isn’t offensive — it’s defense,” Miller said. “We dealt with a little bit of that when we came back.’

“It wasn’t about being 12-0, it was about us as individuals, and you could see it in effort, concentration, details.”

So after the Wildcats allowed NAU to make 4 of 8 three-point shots in the second half Monday and were out-rebounded 18-16 after halftime by their struggling Big Sky opponent, the red flags went up.

Even UA junior guard Nick Johnson saw them.

“I think we’re good, but we can get a lot better,” Johnson said. “Right now we’re a top 10 defensive team, but that was our goal coming into the year. But as a team we know we can be a lot better than that, be the No. 1 defensive team in the country if everyone focuses in on being that. We’ve gotta get ready for this conference season.”

So the goal is to return from their three-day Christmas break a different group than a year ago. Miller said the 13-0 Wildcats discussed doing so after Monday’s game.

“The No. 1 thing that won’t happen this year — because if it happens, it’s going to be addressed right away — is our defense” declining, Miller said. “Our defense has to remain one of the best in college basketball. That is not easy.

“For example, the second half of (the NAU) game isn’t good enough, not by the standards we judge ourselves by. It leads to the next game, and individuals who aren’t playing good enough defense, they’re not going to play.

“Sometimes the offense is going to score on us because they’re really good, but it can’t be because of us. I think that’s the one commitment we’re making to each other when we return from the holidays.”

Sportswriter for the Arizona Daily Star covering Arizona Wildcats basketball