 -- Donald Trump's campaign team admitted there were "some missed opportunities" at Monday's presidential debate, after having time to digest the real estate mogul's performance, sources said. One senior staffer, in a stark admission, said Trump's failures were his own and "more a lack of execution than preparation."

At the same time, members of Trump's family are standing behind the leadership of the campaign, contrary to reports of dissension.

"My siblings and I are thrilled with the current team, as we should be, given the success in the polls and in Monday's debate," Donald Trump Jr. told ABC News today in a statement. "There is no truth to this fabricated lie, and we are excited to be working with these amazing professionals. The business continues to be tremendously successful, as it has for years, given our incredible assets and attention to detail in their management."

The comments came amid intense finger pointing from all levels of the campaign. Trump has blamed the moderator for not addressing topics he wished to discuss. Meanwhile, that staffer said Trump "lost his nerve" in not hitting Hillary Clinton on issues like the attack in Benghazi, even though the campaign arranged to have Benghazi survivor Mark Geist in the audience.

To blame the candidate is evidence of how shaken advisers were after the debate, seeking to shift blame from themselves and those who were responsible for prepping the candidate to the candidate himself.

Sources said that Trump prepared more than was reported but that he should have participated in mock debates and prepared for topics like the birther theory that he pushed for years about President Obama (before disavowing it recently) and his comments about women.

But Trump believed those issues and questions surrounding them, according to one source, were "well within the past." Three sources said they were shocked Trump did not bring up Benghazi, and another said that it was a topic covered in prep sessions.

Hillary Clinton blasted Trump at the debate for language that he has used to describe women and took him to task for pushing birtherism for years after Obama released his birth certificate.

Sources said that unfortunately Trump "did not get through the checklist" but that the campaign feels it has time to prepare for the final two debates. New Jersey Gov. Chris Christie will continue to be a part of sessions, and the team is hoping to simulate the town hall format of the next debate.

But sources said no new prep has taken place for the next debate, on Oct. 9, and the focus right now is on campaigning.