While President Trump has hit the campaign trail hard, holding eight events in the last week, Biden has taken a decidedly different approach, keeping a light schedule in order to prepare for their upcoming meeting.
The former vice president has hunkered down for debate preparations, which are being overseen by Democratic debate guru and Biden's former chief of staff, Ron Klain, according to sources familiar with the preparation.
The preparations also includes Bob Bauer, a senior Biden adviser and former White House general counsel, stepping into the role of Donald Trump to help the former vice president get ready for Tuesday according to a source familiar with the process.
"Joe Biden is very big on preparing," said Patti Solis Doyle, a Democratic strategist and former adviser to Biden, who took part in his 2008 vice presidential debate preparations.
"He understands that this is an opportunity to really speak directly to the American people. And so he wants to make sure he's ready and prepared," she added, noting his fondness for briefing books and discussion of strategy.
In an interview with MSNBC Saturday, the former vice president predicted that his time on the debate stage will be tough, and expects the president will get personal.
"It is going to be difficult. I know -- I mean my guess it's going to be just straight attacks. They're gonna be mostly personal. That's the only thing he knows how to do. He doesn't know how to debate the facts because he's not that smart. He doesn't know that many facts," Biden said in an attack of his own.
Biden aides expect the former vice president to focus on making the case for his own presidency in his time on the stage, with Biden expected to contrast his vision with Trump's record -- particularly his response to the coronavirus pandemic.
It's a message Biden has been honing during his time on the campaign trail, highlighting his view that Trump has failed not only to save lives, but livelihoods as well.
"I'm prepared to go out and make my case as to why I think he's failed, and why I think the answers I have to proceed will help the American people and the American economy, and make us safer internationally," Biden previewed Saturday.
The former vice president will face a tenuous tightrope of pushing back against the president's attacks, without getting mired in continuous he said-he said squabbles.
"That's not going to be Joe Biden's role to play whack-a-mole and hit every Trump lie." Sen. Chris Van Hollen, D-Md., told ABC News. "Let the moderators be the fact checkers here -- otherwise you'd spend your whole time knocking untrue statements from Donald Trump. You wouldn't have time to make your own case."
Biden, with a well known record of gaffes throughout his political career, will likely face intensive scrutiny from the president and his allies, eager to jump on any verbal miscue or mistake as an example of Biden's declining mental acuity--an argument President Trump has tried to make for months, despite some top advisers urging him to tone it down ahead of their debate matchup.
"He's a dumb guy. Always known as a dumb guy. But we look forward to seeing him in the debate. He's got a lot more experience. He's got 47 years. I've got 3 1/2 years. So we'll see. But he's got 47 years of experience," Trump said Saturday during a rally, delivering a mixed message on expectations of Biden's debate performance.
Another challenge for Biden could be keeping his cool amid the president's planned attacks on his son, Hunter Biden, and his business dealings in Ukraine during Biden's vice presidency, despite the younger Biden denying, and not facing any charges of wrongdoing.
It's a topic Biden has shown he is significantly sensitive to on the campaign trail, famously snapping at a voter in Iowa and calling him a 'damn liar' over a question about his son's work in the country.
"If the president goes after his son Hunter, I'm sure Joe Biden will get angry but I don't necessarily think that's a bad thing," Solis Doyle said. "I think the American people want to see a father support his son, and defend him. That just comes naturally to Joe Biden."
While Tuesday will mark the first time Biden takes part in a presidential debate, he does not come to the stage without experience in such high stakes events.
In 2012, Biden faced off with Paul Ryan in his second vice presidential debate, the last time Biden faced an opponent from the opposite party. Four years before that, Biden took on Alaska Gov. Sarah Palin.
The former vice president had more recent practice throughout the 2020 primaries, participating in 11 Democratic debates -- though only one featured a one-on-one matchup.
All told, Biden has participated in 26 vice presidential and presidential primary debates in the 33 years since he launched his first presidential run in 1987, according to a list of debates compiled by the University of Virginia Center for Politics.
"This is a whole different ball game from preparing for a debate with Paul Ryan," warned Van Hollen, who played Ryan in mock debates during Biden's preparation in 2012.
"Preparing the debate for Paul Ryan is one where you're preparing for someone who at least has some respect for the truth and facts," the senator said. "With Donald Trump, he makes it up ... he lies constantly."
Still, Solis Doyle argues that the stakes are much higher for Trump, who enters the debate trailing Biden in a new ABC News/Washington Post poll by 10 points nationally.
"Basically, for Joe Biden the strategy should be to do no harm, to come in and out of this debate with the status quo. I think that the stakes are much bigger for Donald Trump. Donald Trump has to move the needle, because he's losing this race right now and so he's gonna have to do something to really shake it up. And I don't know if he will have that ability in this debate."
ABC News' Ben Siegel contributed to this report