Cruz, speaking at a fairground here in a state that is expected to be one of Tuesday's most competitive contests, was in rare form as he held nothing back in assailing his chief rival's calling card: his success as a world class businessman.
"Say, 'This is my future, this is my kids, this is my grandkids, this is my country, damn it!'" a visibly stirred Cruz said, imploring Georgians to vote with a rare display of profanity. "Stand up and fight for it together."
It was one of the most animated performances of Cruz's entire campaign, jumping quickly from one strike to the next as he belittled, provoked and questioned the man favored to beat him in Georgia -- or as Cruz called him at one point, "little fella."
The Texas senator spent a full three minutes here needling Trump for his reluctance to release his tax returns, which the billionaire has said he will not do until he is cleared of IRS audits. Cruz's unprompted riff was altogether his most extensive critique so far of Trump's personal financial dealings, during which Cruz went as far as to say that it is an open question whether Trump is hiding crimes that he had committed.
"Now this is a man who prides himself on not getting scared of anything," said Cruz, who poked at Trump for "inheriting $200 million from his daddy." "So you're telling me, a few months from now, you may be charged with tax fraud? Now maybe not -- I'm not suggesting it -- I'm saying release the returns and let the people see. Because if we're sitting here in September and October, how much can you imagine the mainstream media salivating over whatever scandal they can paint on Donald Trump?"
Weakening Cruz's argument: the fact that he himself hasn't released additional returns and missed the deadline he set for himself to post them on Friday.
Cruz is staring at the most important day of his presidential campaign, a date that looks increasingly unlikely to now break his way. Cruz had once hoped to win much of the southern states that vote on March 1, but Trump now leads almost everywhere. Georgia, however, is expected to be one of the more competitive states on Tuesday.
And that's where Cruz also expanded two new fronts of contrast against Trump and Florida Sen. Marco Rubio on immigration, which has been a well-worn debate between Cruz and his rivals, and on guns, which hasn't been discussed as much.
As he almost always does, Cruz characterized Republican politicians as theoretically supportive of Second Amendment rights but never willing to spend energy to protect them. But he pushed new opposition research to the crowd here on Saturday.
"Do you know that my two leading competitors have both supported banning guns?" Cruz asked. He claimed that Trump "explicitly supported" some gun control measures by former President Bill Clinton and that Rubio had "voted to ban guns in public parks" as a local official in West Miami.
And on immigration, which has been the main dividing line between Cruz and Rubio, Cruz turned to some history in Georgia to bolster the case that Trump has been equally as inconsistent.
Cruz and Rubio have both targeted the developer for allegedly hiring foreign workers instead of Americans at his properties in the United States, which Cruz says contradicts his hardline rhetoric on illegal immigration.
"Pick a side," Cruz told Trump. "In the Civil War, you couldn't fight for the North and the South at the same time."
Those biting broadsides are a far cry from a few hours earlier, when Cruz was deploring the escalating rhetoric between Trump and Rubio.
"I have to say, I don't think it's a good thing to see candidates bickering," he told reporters in Atlanta.
The Trump-Rubio feud began at CNN's GOP debate
in Houston Thursday when Rubio hammered Trump on immigration, health care, foreign policy and other issues. Trump shot back with a torrent of insults.
Rubio has been trying to position himself as the main Republican alternative to beat Trump, with major backing from the GOP establishment and donor class. But that message got undercut somewhat on Friday, with surprise endorsements by New Jersey Gov. Chris Christie
-- who recently exited the GOP race -- and Maine Gov. Paul LePage