The Trump campaign, reeling from a tough loss in Wisconsin, is moving to discourage anybody considering getting on the Ted Cruz train – by sounding the alarm that the GOP establishment is only using him to get to an open convention.

The campaign unleashed the tough new line of attack against his Republican presidential primary opponent Tuesday after the Texas senator’s big Midwestern victory.

“Ted Cruz is worse than a puppet – he is a Trojan horse, being used by the party bosses attempting to steal the nomination from Mr. Trump,” the statement said.

Trump national spokeswoman Katrina Pierson defended the statement on an appearance on Fox News on Wednesday, saying the so-called establishment has no intention of supporting Cruz at the convention -- suggesting the goal is only to use him to hold back Trump and force a floor fight, and then back somebody else.

“Their loyalty is not with Senator Cruz. However Senator Cruz has now made himself that Trojan horse to push this to a contested convention,” Pierson said. “This is going to be a very serious problem if Senator Cruz continues to go down this path, and then neither Trump or Cruz becomes the nominee.”

Cruz, though, has rejected talk of the establishment swooping in with a candidate of their own, saying the voters “would rightly revolt.”

“This fevered pipe dream of Washington that at the convention they would parachute in some white knight who will save the Washington establishment, it is nothing less than a pipe dream,” Cruz said Monday. “It ain’t gonna happen. If it did happen, the people would quite rightly revolt."

Cruz only bolstered his case that he's gaining momentum in the battle against front-runner Trump with his Wisconsin victory. He scored 48 percent of the vote to Trump's 35 percent, and picked up the lion's share of the state's delegates. Ohio Gov. John Kasich trailed far behind.

The race heads next, though, to New York state where Trump has a commanding lead in the polls.

The criticism of having ties to the establishment is an unusual one for Cruz -- who has portrayed himself as an outsider fighting against what he calls “The Washington cartel,” and until recently has had few allies on Capitol Hill.

Cruz, though, has recently found backing from figures such as South Carolina Sen. Lindsey Graham, former Florida Gov. Jeb Bush and 2012 Republican nominee Mitt Romney, who have offered their support as a way to stop Trump.

These figures have sometimes been open about their endorsement of Cruz merely being a way to stop Trump and not a full-throated endorsement of Cruz himself. Graham once joked that if Cruz was shot in the Senate, no senator would convict him.

The lukewarm endorsements have allowed the Trump campaign to pounce.

Barry Bennett, a senior adviser to the Trump campaign, told FoxNews.com last month that Cruz is being "taken for a ride," and should there be a contested convention, his current backers will abandon him in favor of an alternative candidate.

"The establishment is using him because they want to get to the second ballot, and then they'll pretend they've never heard of him," he said.