The Steel Curtain is taken. The defensive line for the Pittsburgh Steelers had that clever nickname in the 1970's when they won four Super Bowls.

Iron Curtain is available, since the Cold War ended 1991, but that's a geo-political term.

So what should we call the Xavier High School defensive unit that has thrown eight shutouts this season en route to the semifinals of the Class 4A playoffs?

The Gold Curtain? They've certainly been golden, holding opponents to an average of 5.1 points and 132.1 yards per game.

The Silver Curtain, in honor of their silver pants?

Platinum? Bronze? Zinc?

It doesn't really matter, because all the Saints care about is winning two more games and claiming the 2013 state title.

Xavier (11-1) meets Bettendorf (10-2) Friday at 4:06 p.m. in the state semifinals at the UNI-Dome in Cedar Falls. West Des Moines Valley (10-2) plays Dowling (12-0) in the other semifinal at 7:06 p.m., with the winners meeting next Friday.

The Saints feature 10 seniors in the starting lineup on defense. They helped Xavier win 13 straight games last season and reach the finals before falling short against Ankeny, 23-17.

The key?

"Synergy," said Jim O'Connell, the team's veteran defensive coordinator. "They know what I'm thinking. If they don't, we've got a problem. They're a good group of kids.

"They work hard, they study hard," he said. "I don't have to go into great lengths or detail. They know. And that makes it fun to coach."

O'Connell has known these guys for a long time. His son, Colin, is also a senior at Xavier and one of the team's wide receivers. It's a close-knit group.

"I know them so well," O'Connell said. "And they've been around me, so they know how I am. They know how to toe the line, and we have fun at other times too. I think that's made a big difference."

Matt Nelson, Andrew Khairallah, Daniel Vega and Hunter Baldus are Xavier's version of the "Steel Curtain" on the defensive line. Logan Clarahan, Sean Ickes and Nik Ekland are the linebackers. Miles Sullivan, Nick Drahozal, Wes Gardner and Ben Valentine are the defensive backs.

Ekland is the only junior in the group and he's fit right in. The rest of the starters have been classmates for a long time.

"It's pretty special," Vega said. "Obviously we've been playing together since forever. We all know each other really well. That helps."

Nelson credits the coaches with forming a strong unit. "They just get after us," he said. "They're great coaches and they just tell us to do our jobs. That's pretty much what it boils down to."

O'Connell likes having a veteran unit on the field, because it makes in-game adjustments simpler and more effective. "They're the eyes on the field," he said. "They have a lot of input when they come out. We depend on them a lot."

O'Connell feels like he has a lot of coaches on the field, players who are willing to offer opinions and make suggestions. "All 11," he said. "This is the first year that's ever happened. Usually I'll have only one or two guys."

Eight shutouts in one season is outrageous, no matter what level of football you're talking about, but it's not a hot topic of conversation at Xavier, lest they jinx themselves.

"I don't want to think about it," O'Connell said. "And I told those guys on defense - I'll talk about you when we're done. And hopefully we'll talk a lot about them."