Biden had spent the week leading up to the debate at Camp David in Maryland, a presidential retreat where aides helped him prepare with mock set-ups. Trump, meanwhile, largely continued his schedule of rallies.

But from the moment Biden stepped on stage, the Democratic president seemed to wobble, muttering as he approached the podium.

Still, as he faced the first question of the night, Biden came out swinging, seeking to dent Trump’s popularity by attacking the Republican’s leadership during the COVID-19 pandemic.

“We had an economy that was in free fall,” Biden told the room, which was largely empty except for two CNN moderators, Dana Bash and Jake Tapper. “By the time he left, things were in chaos. Things were in chaos. So we put things back together.”

He also mocked Trump’s resistance to COVID-19 safeguards, saying his philosophy echoed the misinformation circulating online about cures: “Just inject a little bleach into your arm, and you’ll be alright.”

But when Trump was given a chance to respond, his opening remarks reflected a characteristic hyperbole the Republican candidate has become known for.

“We had the greatest economy in the history of our country. We have never done so well. Everybody was amazed by it. Other countries were copying us,” Trump said in his opening remarks, quipping later: “Everything was rocking good.”

A critical night in a tight race

The night was a crucial event for both Trump and Biden, as they sought to advance different visions of the US. Trump implied that the country declined under Biden’s leadership. Biden, meanwhile, sought to defend the US’s standing in the world.

“I’ve never heard a president talk like this before. We’re the envy of the world. Name me a single major country that wouldn’t trade places with the United States of America,” said Biden at one point.

“No one thinks we’re weak. No one wants to screw around with us. Nobody.”

Trump, however, fired back at one point: “Joe, our country is being destroyed as you and I sit up here and waste a lot of time on this debate.”

In the lead-up to Thursday’s debate, polls showed Trump and Biden in a tight race, though the Republican appeared to be edging ahead.

A survey from The New York Times and Siena College, released on the eve of the event, showed Trump with nearly 48 percent support, close to four points ahead of Biden, who was around 44 percent.

Political observers noted that Thursday’s performance could deepen that divide.

“I’ve been speaking to Republicans and Democrats since the debate ended,” said Al Jazeera correspondent Alan Fisher. “And the overwhelming view is that this was a very good night for Donald Trump.”

Much of it had to do with stage presence, Fisher continued. He noted that Trump reiterated many talking points from his campaign rallies.

“Yep, Joe Biden called out Donald Trump on his lies, on his falsehoods, on his exaggerations, on things that simply are not true. But Donald Trump looked as if he was in command,” Fisher explained. “Biden didn’t finish thoughts. He looked confused on certain points. And this was a bad night for him.”

Fisher added that the debate will underscore questions about Biden’s age: The Democratic president is 81, while his Republican rival is 78. “This performance is not going to do anything to assuage those concerns.”

Unusual event with familiar talking points

The debate was unusual for several reasons, not least because of its historically early timing: Both Biden and Trump pushed to move the first presidential debate of the election cycle to June, to avoid overlaps with early voting, which begins in some states in September.

But that put the inaugural debate of 2024 ahead of even the major party conventions, where the candidates are officially named the Democratic and Republican nominees.

In another departure from tradition, Biden and Trump bypassed the bipartisan Commission on Presidential Debates to organise the debates themselves, negotiating directly with CNN to host it.

Thursday’s debate, however, was only the first of two presidential debates scheduled for this year, and political observers are hoping that Biden can distance himself from his inaugural debate performance by the time he reaches the second on September 10.

Trump repeatedly slammed Biden on immigration, using heated anti-immigrant rhetoric to conjure fears of violence.

“He wants open borders. He wants our country to either be destroyed or he wants to pick up those people as voters,” Trump said of Biden.

Biden tried to dispel the link between immigration and crime: Studies have shown immigrants, on average, are less likely to commit crimes than US-born citizens.

“There’s a lot of young women who have been raped by their in-laws, by their spouses,” Biden responded at one point after Trump made claims that “there have been many young women murdered by the people he allows to cross the border”.

Biden also tried to call out Trump’s falsehoods when it came to abortion access. Trump made the erroneous claim that Biden and other Democrats were “willing to, as we say, rip the baby out of the womb in the ninth month”.

“You’re lying. That is simply not true,” Biden retorted. “We are not for late-term abortion, period. Period.”

Ad hominem attacks

But the debate devolved at several points into each candidate exchanging accusations that the other was lying or whining.

At one point, they even started to compare their golf games, with Biden challenging Trump to carry his own bag of equipment and Trump mocking Biden’s swing.

Biden slammed Trump for media reports that the Republican president called veterans “suckers and losers”, invoking the loss of his own son, Beau Biden.

“My son was not a loser or a sucker. You are a loser. You are a sucker,” Biden told Trump.

But even there, Trump responded forcefully, saying the media report was a fabrication: “He made up the suckers and losers, so he should apologise to me right now.”

When Biden tried to press Trump about his lukewarm reaction to the 2017 Unite the Right rally in Charlottesville, Virginia — which saw white supremacists march through the streets with tiki torches — Trump likewise attempted to deflect.

“For three and a half years, we’ve been living in hell,” Trump responded. “This is a hundred times Charlottesville, a thousand times Charlottesville.”

Democrats rally around the president

But despite criticisms of Biden’s debate-night performance, Democrats rallied around the president in the hours after the event, repeating accusations that Trump represents an existential threat to US democracy.

“You don’t turn your back because of one performance. What kind of party does that?” said California Governor Gavin Newsom when asked if Biden should step down. “This president has delivered. We need to deliver for him at this moment.”

Vice President Kamala Harris, Biden’s running mate, acknowledged weaknesses but said the president turned out a good performance in the end.

“Yes there was a slow start, but it was a strong finish,” she said in an interview on CNN.

However, Fisher, the Al Jazeera correspondent, reported there were rumblings about finding a replacement candidate, should Biden no longer be perceived as having a viable path to victory.