Joe Biden said he wasn't prepared for the friendly fire he's taken from Democrats over busing, and instead tried to refocus his message on differences with President Donald Trump.
"I took on successfully, and I prosecuted the big banks, when they preyed on homeowners", Harris said, touting her record as attorney general of California.
Mr Biden was asked whether it might be Ms Harris, who confronted him at last week's Democratic presidential debate over his stance on bussing in the 1970s.
In an interview aired Friday on CNN, Biden said, "I think it helps having a woman on the ticket".
In what was one of the most heated exchanges of the first Democratic primary debate, Harris came after the former vice president for his record on race. "And if I don't win, it'd be great to have a female president".
Biden pointed out that most swing districts were won by moderate Democrats in the 2018 elections, and he believes that is what the upcoming presidential election "is about". Biden had recently been under fire for touting his ability to work with two segregationist senators who were strongly opposed to the civil rights movement. "But if you make it, I will see you at the Starting Gate!"
Biden faulted Trump on policy throughout the interview, including his handling of China - "while he's tweeting, China's going to own the 5G market"- and North Korea. "I'm going to let you die, ' man?" "Show me something ahead of time", Biden said of the Hermit Kingdom, faulting Trump for his openness with the rogue regime and despot Kim Jong Un.
She told the audience, "I prosecuted the big banks when they preyed on homeowners". "I've prosecuted the pharmaceutical companies when they preyed on seniors".
Biden said he would beat the "divider-in-chief" by "pointing out who I am and who he is and what we're for and what he's against", adding that he will "fight without being personal" in this campaign.