Tevin Hood is at his third school in four years of college football.

He has had hundreds of teammates, has played in close to 30 games and has recorded 41 tackles. But Hood — and this is putting it nicely — has never been on a college defense that’s been very good.

As a freshman, he played on a Duke unit that gave up 450 yards per game. His University of San Diego team gave up 350 yards per game, and every Arizona fan knows how last season at the UA went. The Wildcats surrendered 499 yards per game and ranked third to last nationally in total defense.

So pardon Hood if he’s soaking in the defense’s early stellar play this season.

“The last time I played on a defense that was dominant was when I was in high school,” said Hood, who prepped at Chandler Hamilton High School and had 19 sacks his senior season. “It’s nice to get back to that feeling. It keeps the fear in the offense and allows us to control the game from a defensive standpoint.”

Though they’ve played only NAU and UNLV, the UA defense has in fact been dominant this season.

Some proof:

• The UA’s defense has scored more touchdowns (three) than it has given up (two).

• After shutting out NAU, Arizona limited UNLV to just 13 points; coordinator Jeff Casteel’s defense gave up fewer than 17 points in a game only once last season.

• The UA has 16 tackles-for-loss through two games and is on pace for 96 after having 67 last season.

“There’s a better understanding of what we’re doing defensively since it’s our second year,” coach Rich Rodriguez said. “We have a little bit more depth, more guys are able to play than a year ago, and we’re healthier certainly than we were a year ago at this time.”

Here are three reasons why the UA has been more effective so far this season.

1. They’re deeper. The depth has shown up most on the defensive line. Hood and fellow starters Sione Tuihalamaka and Reggie Gilbert are getting more plays off and remaining fresher for the third and fourth quarters.

Senior Justin Washington, junior Kirifi Taula and freshmen Dwight Melvin and Kyle Kelley have all played meaningful snaps the first two games.

“I feel the same the whole game; I’m always wired,” Hood said. “But, there is definitely less of a beating because we are able to rotate out more often. It’s a good feeling.”

Hood and Tuihalamaka have already combined for five tackles-for-loss this season. The duo produced five all of last season.

Washington has also been productive with five tackles, including one for a loss and Melvin — who made his debut against UNLV after being nagged by an injury in fall camp — had a tackle-for-loss against the Rebels.

“Our depth has to show up even more as we get going,” Rodriguez said. “We have an open date after (UTSA) and then a semi-open date, and then we play seven in a row, so our depth is going to be tested down the road.”

2. They understand Casteel’s system better. Casteel’s 3-3-5 “odd stack” attack can take some getting used to. There are wrinkles to every team’s defense, but even more with Casteel’s unique style. Casteel’s unit returned 10 starters from last season, and it’s been easy to tell through two games that the players are more comfortable and confident with the game plan.

The defensive coaches have been able to use more formations and plays earlier in the season than last year because of the familiarity.

“We are able to blitz a little more than last year,” Hood said. “We can also run some different line stunts that we weren’t able to last year. The more we are able to move allows us to disrupt the play a little more effectively.”

The UA has four sacks in the two games; evidence that the system is being picked up better to a man.

3. They’re making more game-changing plays. The defense already has five takeaways in two games — four of them interceptions.

Takeaways can obviously swing the momentum of a game, and they’ve done just that for the Wildcats against UNLV and NAU.

Against the Rebels, UNLV turned the ball over three times in seven possessions. Linebacker Marquis Flowers started it off with a fumble recovery — that Hood forced — and returned it 36 yards to inside the 10-yard line. Jake Fischer and Tra’Mayne Bondurant each had interception returns for touchdowns.

By the time those turnovers had been created, the game went from a 10-0 UA lead to a 45-6 advantage.

Turnovers are key for any defense, but with the UA’s lack of size, it’s even more crucial.

“I really just think we play more ferociously than other people who might be bigger,” Hood said. “We are more relentless and that allows us to make up for being undersized.”

Contact reporter Daniel Berk at 573-4330 or dberk@azstarnet.com. On Twitter @DSBerk.