The Falcons have surrendered more than 20 points just once this season, in a 23-16 overtime loss at Utah.

"A lot of times, really good defenses tend to do one or two things really well," UNLV coach Mike Sanford said. "(The Falcons) play a lot of different coverages, more than most teams would play. And the other thing is they mix coverages well, and there isn't a whole rhyme or reason to when they do it and why.

"I think that creates problems for quarterbacks."

Statistics bear that out.

Air Force -- employing a healthy dose of the zone blitz -- is No. 1 nationally in pass defense (127.2-yard average), No. 7 in total defense (263.7) and No. 9 in scoring defense (12.9-point average).

The Falcons have intercepted 11 passes and, having also recovered 13 fumbles, rank second in turnover margin with a plus-1.8 average.

Air Force utilizes a 3-4 alignment and likes to disguise its coverages. So what UNLV quarterback Omar Clayton sees before the snap isn't necessarily what he'll get.

"You familiarize yourself with what they've done before and what they did against you last year," Clayton said, "so that things kind of click when you start to see certain movements, certain alignments. As long as you prepare right, you have a fighting chance."

Senior linebacker John Falgout, who leads the Falcons with 80 tackles, said a big key to the defense is being able to confuse opposing offenses.

"It's the same way for us when we face an offense that's going to give us a bunch of different looks that we have to prepare for," Falgout said. "The fact that we're able to come out with a few different fronts and different coverages, we can show some different looks and have opposing offenses not quite be ready for what they're going to see."

Falgout acknowledged that the team's run-based offense, which controls the ball for nearly 32 minutes per game, helps keep the defense fresh.

But Air Force features that attack every year, and last season the Falcons ranked in the middle of the Mountain West in total defense, allowing 341.5 yards per game.

So coaches decided to tweak some things.

"We really have narrowed down the amount that we have done," Air Force coach Troy Calhoun said.

It's still more than most teams, though.

And more effective.

"Coming into the season we set some expectations we wanted to be really good," Falgout said. "We've worked hard to get to where we are, and so as the season has gone along, I don't think we've been too surprised."

• INJURY UPDATE -- Linebacker Ronnie Paulo (knee) practiced Wednesday and is expected play Saturday but not start.

Contact reporter Mark Anderson at manderson@reviewjournal.com or 702-387-2914. Read the latest UNLV football updates at lvrj.com/blogs/unlv_sports.