The ad, "never, ever," features Dr. Cristina Beato, the former Acting Assistant Secretary of Health in the U.S. Health and Human Services Department from 2003-05, his supervisor while he was U.S. Surgeon General under George W. Bush.

Beato retells the testimony she gave under oath to Congress about Carmona coming to her house and angrily banging on her door one night.

"Carmona is not who he seems. He has issues with anger, with ethics and with women. I have testified to this under oath to Congress. Richard Carmona should never, ever be in the U.S. Senate," she says.

Beato offered the same account of an angry, difficult man during a House Oversight and Government Reform Committee investigation into the surgeon general's office under the Bush White House, but previous reports indicate she and Carmona shared a rivalry during their time under Bush. Carmona was not charged with any wrongdoing during the investigation.

But he was asked about his "temperament" during the first candidates' debate, on Wednesday night, and this new ad indicates Flake's campaign hopes to raise questions about it to drain what has thus far been remarkably strong support for the Democrat.

The two campaigns released dueling internal polls on Wednesday afternoon that each put themselves ahead, but the reality of the race is more likely somewhere in the middle.

Thus far, Flake has largely focused on tying Carmona to President Obama and liberal policies, but over the past two weeks his campaign has shifted to a focus on his past as CEO of the Pima County health care system -- a position from which he resigned due in part to the system's deep debt -- and Beato's allegations.

But Carmona spokesman Andy BarrGarland (Andy) Hale BarrCook Political Report shifts two House race projections toward Dems GOP super PAC targets House districts with new M ad buys A bipartisan approach to protecting racehorses MORE called the ad false and "deplorable."

"These allegations are completely false. Dr. Beato is a partisan who was caught trying to politicize science at HHS and couldn't be confirmed to a post because she lied on her resume. It's no secret that Dr. Carmona pushed back on her attempts to spin science for political gain, but this accusation is a work of fiction," he said.

Watch the ad: