MIAMI — Hours before the first debate, a trio of senior Biden advisers said the strategy for Thursday was simple: Let Joe Biden be Joe Biden. He would deflect attacks on his record and pivot to his forward-looking agenda — one of “transformational change.”

But as one top Biden ally had said earlier: “Everybody has a plan until they get punched in the mouth.”

Biden had acquitted himself well in debates in his career, including under significant pressure. As vice president in 2012, he rose to the occasion when it mattered most after Barack Obama’s lethargic opening debate performance against Mitt Romney.

But there was still nervousness among his team leading up to Thursday, his first major public test in years where it was his own record under scrutiny. The biggest concern: that no matter how much they prepared him for the likely attacks to come, his pride in his own record would manifest as defensiveness, if not outright anger, at a sustained attack. It did in one such prep session this week with top aides at a Wilmington, Delaware hotel.

After Thursday's debate, the question is whether the Biden campaign has been right in its belief that the former vice president has a credibility with voters that can withstand the kind of punch delivered by Sen. Kamala Harris of California, and that any attacks could backfire on those who make them.

Top aides traveling back to Washington Friday morning insisted that was still the case. Asked what’s next, a top Biden campaign official focused on nuts and bolts: hiring more field organizers in the early states and finishing the fundraising quarter strong. Biden deputy campaign manager Kate Bedingfield tweeted that the campaign had its strongest fundraising hour since its Philadelphia kickoff rally in May.

Biden will have an opportunity Friday to quickly try and contain the fallout with a scheduled address to the Rainbow/PUSH Coalition International Convention, where the focus will be on civil rights and racial justice. Biden will have more than the one-minute or 30-second time limit the debate allowed for him to address the charges.

“This is super heavy stuff that can’t play out in a ten-person debate. Harris had a strategy that took advantage of that reality,” the official said.

The official also insisted accounts from reporters on Twitter of staff panic were dead wrong.

“We are not naïve that he isn't going to get attacked. It’s the only way candidates get headlines,” the official said, adding that they are focused on what matters to voters in New Hampshire, Iowa and South Carolina, not on the conversation on Twitter.

And the reaction from allies around the country was largely positive, “until they turned on cable news," the official added.

Another Biden operative at the campaign headquarters said the atmosphere was “remarkably calm.” But another senior aide said the mood varied — with concern especially higher among the staff new to the Biden orbit.

The campaign had endured a number of negative storylines already for a young campaign — one even before Biden officially launched his bid — but have so far been able to point to polls showing their candidate with a strong lead to back up their assertion that the conversation on cable news and on Twitter was not reflective of reality.

But at least in the initial hours the campaign was still working to present the best response. A call with campaign surrogates immediately after the debate did not address the Harris exchange, and no questions were taken, according to one participant.