Cruz said his campaign is the only one that can stop Trump. (REUTERS/Brian Snyder)

CEDAR RAPIDS, Iowa -- Sen. Ted Cruz told a group of pastors here that they can help blunt the national momentum of Donald Trump if they work to help Cruz win next week's Iowa caucuses, and that his campaign is the only one that can beat the real estate mogul.

Cruz, who is battling Trump for first place just a week from this state's caucuses, told a ballroom full of pastors at a lunch here that the race between the two men is an "absolute dead heat."

"If Donald wins Iowa he right now has a substantial lead in New Hampshire. If he went on to win New Hampshire as well there’s a very good chance he could be unstoppable and be our nominee. And the next seven days in Iowa will determine whether or not that happens," Cruz said at a policy briefing luncheon put on by the American Renewal Project, an organization of conservative pastors that has held events with numerous candidates in Iowa.

Attendees of the luncheon, as well as a dinner in Des Moines Monday night, said the turnout shows that Cruz has substantial support among religious conservatives here and, if they turn out to the caucuses Monday, they could push Cruz over the edge to a win.

[Ted Cruz asks Iowans for a favor: Prayer]

Cruz has been competing for the evangelical vote with former Arkansas governor Mike Huckabee and former senator Rick Santorum, who won the Iowa caucuses in 2008 and 2012, respectively. Both are polling in the low single digits and have little money in the bank. The Cruz campaign, on the other hand, raised more than $45 million from its March launch through the end of 2015, and a constellation of super PACs supporting the Texas Republican raised at least $38 million as of June 30.

"So even if you’re thinking about another candidate the simple reality is there is only one campaign that can beat Trump," Cruz said.

Cruz, whose campaign is resetting expectations after coming under siege as the presumptive favorite here, said there is no guarantee that he will win, making mobilizing pastors all the  more important.

"What I’ve told people is I can’t guarantee we’ll win. I don’t know that. That’s out of my hands. I believe we have a path to victory. I believe we put the team in place, I believe we have a winning strategy," Cruz said. But what I can guarantee you is at the end of the day, everyone that’s been a part of this will be able to look in the mirror and be proud."

[Ted Cruz, under siege in Iowa, tries to play ‘underdog’]

As he has on the campaign trail this week, Cruz painted Trump as a false conservative who changed his positions on abortion, same-sex marriage and other issues out of political expediency, not principle.

“Now I will note if you have a candidate who has never defended marriage, who has never defended religious liberty, we should not be surprised if they get to the Oval Office and do not defend marriage and do not defend religious liberty. Do not listen to our words, look to our actions," he said.

Cruz has spent the entirety of his campaign assiduously courting the support of evangelical Christians. His pastor father, Rafael Cruz, has been deployed around the country to meet with faith leaders; Cruz's Iowa state director has joked that he spent more time in Iowa this past summer with Rafael Cruz than with Ted Cruz. The candidate and his wife have also spent time cultivating relationships with faith leaders. He has snagged many prominent endorsements from national evangelicals and here in Iowa has the support of two of the state's influential evangelical leaders. The campaign has sought to have a pastor coordinating outreach in each of the 99 Iowa counties.

[Cruz’s evangelical outreach shifts into high gear]

Cruz told the pastors that the stage of the race is such that it is up to them to decide its outcome here, and that they should make it their "personal mission" to motivate congregants, friends and others to caucus.

“If each of you simply takes it on as your responsibility that every member of your congregation will show up and caucus and will caucus for someone who defends biblical values, someone who has a record, not campaign rhetoric, that’s how we keep getting burned," Cruz said.

Brad Cranston, a pastor from Burlington, Iowa, who is supporting Cruz, said he believes the Texas senator will prevail next week and isn't worried about Trump's momentum -- he believes it will help embolden Cruz supporters to get out and caucus.

"Am I worried? No. In fact, if anything, I think this and who knows, this may be better than being listed as being on top because it will help people say I need to get out there," he said. "If it was reversed it would be, well, he can do it without me."