William Cummings

USA TODAY

Donald Trump confidently declared victory in the final debate with a 3 a.m. tweet, but the cameras caught some body language from the Republican nominee at the close of Wednesday night's debate that appears to indicate he wasn't all that thrilled with the way things went.

A flash of anger comes over Trump's face and he appears to grit his teeth as he angrily rips a page from his notepad. He then appears to collect himself as Hillary Clinton crosses the stage to shake hands with debate moderator Chris Wallace.

Trump was calm and cool early in the debate, but Clinton was able to get under his skin, and by the end, Trump was clearly agitated. He finally snapped as Clinton answered one of the last questions, which focused on Social Security. "Such a nasty woman," Trump interjected after Clinton implied he would find a way out of paying into the entitlement program.