Biden used the opportunity Friday in Arlington to take jabs at former President Donald Trump, whom he linked to McAuliffe's Republican opponent, Glenn Youngkin. Trump endorsed Youngkin, who won the Republican primary last month.
"I ran against Donald Trump and so is Terry," Biden said. "I whipped Donald Trump in Virginia and so will Terry. I tell you what: The guy Terry's running against is an acolyte of Donald Trump, for real."
Biden won 54% of the vote in Virginia last year, nabbing the state's 13 electoral votes.
Speaking to a group of about 3,000 McAuliffe supporters, Biden also took issue with Trump's downplaying of the Jan. 6 attack on the U.S. Capitol.
"Saying, 'I was told there were a lot of peaceful, wonderful people,'" Biden said, questioning Trump's assessment of the day.
Youngkin's spokesman, Matt Wolking, told The Washington Post, "it's totally dishonest for Terry McAuliffe to use President Trump's endorsement to smear Glenn Youngkin, when McAuliffe is actually friends with Trump and took thousands of dollars from Trump to fund his campaign.
Biden also spoke to the McAuliffe supporters about the rise of COVID-19 cases throughout the country and, specifically, Virginia.
"I know folks are watching the number of cases rising again and are wondering what it means for them. Well, here's the truth. If you're fully vaccinated, you're safer with a higher degree of protection but if you're not vaccinated, you are not protected.
"It's not about red states or blue states or guys like that. It's about life and it's about death."
Nearly 50,000 new cases were reported Friday, a 173% increase over the past two weeks, and daily deaths have increased 20% to 271, according to The New York Times. In Virginia, there were 543 new cases reported Friday, a 171% increase, and an average of 3.3 new deaths.
McAuliffe and Youngkin are competing to replace outgoing Democratic Gov. Ralph Northam -- Virginia's Constitution prohibits officeholders from holding consecutive terms.