(STATS) - Taking a look at the Big Sky standings, it appears there's a typo next to Southern Utah's name.

No, it's not that they're atop the conference with a 3-0 record, though that is a little surprising considering they won a total of three Big Sky games a year ago.

The error looks like it's under the column for points allowed, where there's a "3." That's no misprint, however, as the Thunderbirds have allowed just one field goal to go with a pair of shutouts in three league games.

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Southern Utah's defense was a liability a year ago, ranking 109th out of 124 FCS schools in scoring by allowing an average of 35.6 points. The Thunderbirds (4-2, 3-0) returned six starters but lost top returning tackler Chinedu Ahanonu to LDS Church missions.

A pair of STATS FCS Preseason All-America Team members in end James Cowser and safety Miles Killebrew returned to the defense, however, as did linebacker Matt Holley, who missed all of last season with an injury after leading the team in tackles in 2013.

Led by those three seniors, the defense is dominating, allowing Big Sky lows of 317.8 yards per game and 12.8 points per game. Southern Utah has allowed eight scrimmage touchdowns - the fourth-fewest in the FCS.

"Our coaches do a very good job of preparing us each week for our assignments," said Killebrew, whose 51 tackles are two fewer than Holley for the team lead. "We don't do anything out of the ordinary, we just have each others backs on defense and just do our assignments and the results show."

The results have Southern Utah tied atop the conference with seventh-ranked Eastern Washington - quite an achievement for a team picked to finish eighth in the Big Sky in both the preseason coaches' and media poll.

They've outscored opponents 173-10 during a four-game winning streak, beating Northern Colorado 30-3, and Weber State and Sacramento State by identical 44-0 scores in conference games. Their only two losses came in the season opener to Utah State, which is atop the Mountain Division of the Mountain West, and at No. 6 South Dakota State the following week.

"I think if we start thinking in terms of trying to win 44-0 we're likely to lose 44-0," coach Ed Lamb said. "We just have to take care of what we do on offense, defense and special teams."

Last week against Sacramento State, the Thunderbirds tallied five sacks and 10 tackles for loss while limiting the Hornets to 10 first downs and 187 yards - the fewest they've allowed since 2010.

Kyle Hannemann intercepted his third pass, tying him with Mike Needham for the team lead. Southern Utah is tied for the FCS lead with 13 interceptions and its plus-11 turnover margin is the best in the nation.

"We've been going through opponents plays, going through film just looking at it over and over again," said cornerback Josh Thornton, who has two interceptions. "We practice it every day, we're put in the perfect position to make the play and you've just got to do it. It's not about just going out and trying to be a superhero, it's not about doing something outside of your assignment."

The secondary is making plays in part because opposing offenses are game planning on how to contain Cowser. The preseason Big Sky defensive MVP has team highs of three sacks and seven tackles for loss after setting a conference record with 28 1/2 tackles for loss a year ago. The previous record was held by Carolina Panthers defensive end Jared Allen.

Overshadowed by the dominating defense, Southern Utah's offense is more than holding its own. The Thunderbirds are fourth in the Big Sky in scoring at 32.0 points per game and are averaging 43.3 during their winning streak.

Senior Ammon Olsen, a transfer from BYU, threw for 421 yards and matched the school record with five touchdown passes as the offense amassed 570 yards - its highest total since 2004 - last week in its first game under offensive coordinator Justin Walterscheid. The former running backs coach took over the reigns of the offense after Gary Crowton stepped down for personal reasons following the bye week.

"That first play I was hoping we would gain three yards or something, just a positive play, and first play we got a first down on about a 12-yard gain and then it kind of just felt like the game was on," Walterscheid said. "I got into the flow of things and put it more in the player's hands and stuck with the game plan, and those guys made it happen."