Kelli Ward got the blessing Tuesday of President Donald Trump’s former political guru in her U.S. Senate primary campaign against GOP incumbent Jeff Flake, a race that could determine whether Republicans keep control of the Senate in 2018.

Steve Bannon’s public endorsement at a Scottsdale rally appears to be his first in a self-declared “revolt” against the Republican establishment.

Flake, one of Trump’s harshest critics in Congress, is a top target.

“It's an open revolt and it should be,” Bannon told the crowd of several hundred at the Hilton Scottsdale.

“When they attack a Donald Trump and a Dr. Kelli Ward, it's not Donald Trump and Kelli Ward they're trying to shut up, it's you they're trying to shut up."

The endorsements by Bannon and conservative radio talk-show host Laura Ingraham, who also spoke at Tuesday’s rally, stand out as the most significant public support Ward has received in almost three years as a U.S. Senate candidate.

Ward lost the 2016 GOP primary to Sen. John McCain, then barely took a breath before announcing she would challenge Flake in 2018.

Bannon’s seal of approval also indicates the Trump camp has given up on finding an alternative to Ward, who some have viewed as either too weak to beat Flake in a primary or too far to the right to win a general election.

Trump hasn't formally endorsed Ward, but he tweeted support prior to his last visit to Phoenix.

Bannon brings more than his voice to Ward’s campaign.

He runs Breitbart News, which is a bullhorn for the GOP’s “drain the swamp” crowd, Ward’s natural habitat.

The billionaire who funded Breitbart, Robert Mercer, was on Ward’s side a year ago against McCain.

In 2016, Mercer injected $200,000 into the cash-starved Ward campaign through a super PAC, to pay for last-minute TV ads attacking McCain.

This year, he has donated $300,000 to a super PAC supporting Ward.

Mercer would have to write a seven-figure check to keep Ward financially competitive with Flake.

Ward has raised $1 million this year but has just $250,000 in cash on hand.

Flake raised $1.1 million in the third quarter alone, and has $3.4 million in cash on hand.

Polls show Flake trailing Ward, a physician and former state legislator from Lake Havasu City, by almost 20 points. The primary is 10 months away.

But Flake, a first-term senator, can count on support from conservative PACs, Senate Majority Leader Mitch McConnell’s campaign fund, as well as establishment Republicans whom Bannon has in his sights.