Naomi Biden rages against Donald Trump after Beau and Hunter discussion during presidential debate

Naomi Biden’s father, Hunter Biden, was a focus of attack for Donald Trump during the first debate

As Joe Biden received and returned insults across the debate stage, his granddaughter Naomi Biden brought the fighting words online.

“I wouldn't have survived 5 minutes on that stage without slapping him across the face - and I don't think I'm alone in thinking that,” she tweeted at the end of the debate.

“So tell me how someone Trump calls “sleepy joe” and says is on uppers could wade through an hour and a half of this nonsense.”

That “nonsense” was a debate performance from both candidates widely criticized as a train wreck that moderator Chris Wallace was unable to control.

Donald Trump was rebuked for constant interruptions while Mr Biden fired back at the president, calling him a “fool” while telling him to “shut up and keep yapping”.

Families of both candidates featured prominently in Tuesday night’s debate as the president attacked Naomi’s father, Hunter Biden, repeating allegations that he received $3.5 million from a Russian oligarch while his father was vice president in 2014.

“Here’s the deal. You want to talk about families and ethics? I don’t want to do that. His family, we can talk about all night,” Mr Biden replied, referring to Mr Trump’s children.

Away from the debate stage, Ms Biden seemed to take particular offence attacks on her grandfather’s stamina as she referenced the Trump campaign’s repeated claims he must be on performance enhancing drugs.

Mr Trump, meanwhile, was more direct during the debate performance while targeting Mr Biden’s son, Hunter, saying he was kicked out of the military for a cocaine problem.

"My son, like a lot of people we know at home had a drug problem," Mr Biden said. "He’s overtaken it. He’s fixed it. He’s worked on it and I’m proud of him."

Mr Biden also drew the focus onto his deceased son Beau Biden, referencing the Atlantic’s report that alleged the president disparaged troops.

“He was not a loser, he was a patriot and the people left behind there are heroes,” Mr Biden said.

Mr Trump dismissed the comment, saying “I don't know Beau, I know Hunter.”

Eric Trump and Donald Trump Jr, meanwhile, were uncharacteristically quiet in the immediate aftermath of the debate.