After the fourth Democratic debate, at least a few of the presidential candidates received financial validation.

Senator Amy Klobuchar, Mayor Pete Buttigieg and Senator Bernie Sanders' campaigns are all reporting significant fundraising boosts for the 24-hour period following the primetime event in Ohio on Tuesday.

During that time, Klobuchar raised $1.1 million in donations, which amounts to nearly 25% of what she raised from July through September, according to her campaign. It was not only her campaign's best day in online fundraising to date, her team also gained more new supporters than on any other day.

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This comes after Klobuchar took aim at one of the current Democratic frontrunners, Senator Elizabeth Warren, for evading 'yes' or 'no' questions on whether taxes would go up for the middle class under Medicare for All, which Warren supports.

"At least Bernie's being honest here and saying how he's gonna pay for this, and that taxes are gonna go up, and I'm sorry Elizabeth, you have not said that, and I think we owe it to the American people to tell them where we're gonna send the invoice," Klobuchar said during the debate.

The Minnesota senator also went after Warren over her proposal to tax the wealthy's assets.

"I want to give a reality check here to Elizabeth," Klobuchar said, "because no one on this stage wants to protect billionaires. Not even the billionaire (Tom Steyer) wants to protect billionaires. We just have different approaches."

Massachusetts Senator Elizabeth Warren looks on as South Bend, Indiana, Mayor Pete Buttigieg speaks during the fourth Democratic primary debate. SAUL LOEB

Buttigieg was more aggressive on Tuesday than he had been in previous debates. And it seems to have paid off. His senior adviser, Lis Smith, tweeted that his campaign received more than $1 million from "tens of thousands of donors" and saw more traffic to their website in the past 24 hours than any other day.

Like Klobuchar, the South Bend, Indiana, mayor went after Warren over Medicare for All and any associated tax increases during the debate.

"We heard it tonight, a 'yes' or 'no' question that didn't get a 'yes' or 'no' answer," he said after she was asked about her support for the health care plan.

Buttigieg also got into heated exchanges with Beto O'Rourke over the former Texas congressman's call for mandatory gun buybacks.

"I don't need lessons from you on courage — political or personal," Buttigieg said to O'Rourke over gun legislation. "Everyone on this stage is determined to get something done."

Buttigieg also went head-to-head with Representative Tulsi Gabbard over foreign policy. Both are military veterans, but Buttigieg told Gabbard she was "dead wrong" for previously supporting U.S. troop withdrawals from Syria.

Vermont Senator Bernie Sanders speaks during the Democratic Presidential Debate at Otterbein University on October 15, 2019 in Westerville, Ohio. Getty

Tuesday's debate was Sanders' first public appearance since he had a heart attack earlier this month. The Vermont senator said he was "feeling great" on stage, and his brief absence from the campaign trail hasn't hurt his fundraising lead. After the debate, his campaign announced that it raised $620,000 from more than 40,000 contributions.

Sanders leads all Democratic candidates in fundraising, with more than $33 million cash on hand as of September 30. He also had the best quarter of any 2020 presidential candidate this cycle, raking in nearly $25.3 million dollars from July through September.

By CBS News' count, Sanders and Buttigieg have both already qualified for the next debate on November 20 in Georgia. Klobuchar has so far met the fundraising threshold but not the polling one. Candidates have until November 13 to meet both.