As a kid growing up in Chicago, Steve Johnson learned the value of a sturdy defense by watching Dick Butkus and the Bears. That lesson stuck with him when he took over the Bethel football program in 1989, as it foundered at the bottom of the MIAC.

The Royals required a complete overhaul just to become competitive. The surest way to start, Johnson believed, was to put his best players on defense. "And we never left that," he said. "I don't want to take away from the offense, but we start with defense."

That idea has become the Bethel identity. Entering Saturday's game at No. 3 St. Thomas, the Royals are surrendering 11 points per game, the eighth-best mark among NCAA Division III teams. Their unwavering excellence on defense transformed them into a MIAC powerhouse; this season, it has led them to a 5-0 record and No. 7 ranking.

Tommies coach Glenn Caruso -- whose team also is 5-0 -- said it's particularly impressive that Bethel has maintained its defensive strength year after year. It has recruited speedy, hard-hitting players who buy in to a culture built on trust, accountability and love for one another. Together, they hold opponents to a MIAC-low 263.4 yards per game.

"We expect each other to be great," said safety J.D. Mehlhorn, a junior who has two interceptions this season. "The way our schemes work, one guy might make a tackle, but a lot of other guys doing their jobs led to that. Individual pride goes out the window, because we know if we work together, we're hard to stop."

Bethel finished the 2011 season ranked No. 7 in the nation in total defense (242.4 yards per game) and 14th in scoring defense (13.8 points per game). All-MIAC performers Seth Mathis, Erik Smith and Brett Skoog returned to anchor an experienced lineup this season.

When Mathis, a junior linebacker, came to Bethel, he said, he was nurtured by two previous all-MIAC linebackers. Billy Morgan and Ross Petterson helped Mathis learn the Bethel way: Know your duties and perform them well. Trust your coaches and teammates to do the same. Be generous with praise, assistance and affection.

Mathis said the Royals' 3-4 defensive scheme requires players to work in concert, with linemen helping linebackers and linebackers aiding safeties. Defensive end Luke Buttenhoff is their biggest starter at 6-3, 255 pounds, and nose guard Gavin Maurer (6-0, 228) was recruited elsewhere as a free safety. Bethel's players make up for that by being quick, intelligent and committed -- and by hitting with a ferocity that belies their size.

"We play fast, and we play together," said Mathis, whose 76 tackles in 2011 made him a first-team all-MIAC selection. "We pride ourselves on flying to the ball and making big hits. And everybody has that walk-on mentality, that chip on our shoulder."

Mathis, Skoog and Mehlhorn also credited an emphasis on fundamentals -- as dictated by defensive coordinator Mike Fregeau -- for Bethel's consistency. Mathis already is doing his part to keep it going, emulating his elders by schooling young players in the Royals' defensive culture.

Johnson said that Bethel's defensive prowess puts a little pressure on the offense, which doesn't want to let its team down by not scoring. The Royals' offense has diversified this season, with sophomore quarterback Erik Peterson throwing the ball more than his predecessors. That could be a factor against St. Thomas, which has the nation's fifth-best defense against the run (46.8 yards per game).

The MIAC is stronger overall this season, and the Royals have earned one-point victories in each of their past two games. Saturday marks the fourth week in a row in which they have played an undefeated team.

"The last two weeks showed us we have some resolve," Mehlhorn said. "We know we can trust each other in those tough situations. We're in this together. That's what our program is about."