Mitt Romney's presidential campaign has parted ways with debate coach Brett O'Donnell, a Romney campaign source confirmed Friday.

O'Donnell, a former Michele Bachmann adviser who also did debate prep sessions with John McCain and Sarah Palin in 2008, was given credit in several media reports as the man behind Romney's impressive back-to-back debate performances in Florida.

But a source inside the campaign told CNN Friday that O'Donnell's role "was vastly overblown."

O'Donnell was present in the spin room after the CNN debate in Jacksonville giving credit to Romney for his preparation and work habits.

That night, O'Donnell told CNN that Romney realized after his South Carolina primary loss that he needed to "make some changes strategically" in his onstage message.

"He knew he had to engage Newt more and be better on a couple of answers," O'Donnell explained. "He worked really hard to get them right, and tonight I saw a vast improvement."

But in the days after the Florida debates, some Romney advisers groused privately that O'Donnell was being given too much credit for Romney's performances, and proactively emailed reporters to downplay his role in the campaign.

O'Donnell did not respond to an email seeking comment.