Democratic U.S. President Joe Biden and his Republican rival Donald Trump took the stage on Thursday night for a debate that offered voters a rare side-by-side look at the two oldest candidates ever to seek the U.S. presidency.

Here are some of the major takeaways:

HOARSE AND BUGGY

Viewers learned little new about where both candidates stood on the main issues, but arguably that is not why many tuned in.

The leading question going into the debate was how the two men, both of whom have faced questions about their fitness for the job, would handle themselves on stage.

The early going favoured Trump, 78, who appeared forceful and energetic when compared to the 81-year-old Biden, who spoke in a hoarse, halting voice and offered sometimes meandering replies or trailed off during his answers to several questions.

The White House said the president was suffering from a cold, but only after Biden turned in a fitful performance in the opening minutes of the debate.

Trump largely refrained from speaking over Biden, showing the kind of restraint that eluded him during the candidates' first debate in 2020.

For his part, Biden found better footing later as he began to defend his record and tear into Trump's character. But the images that millions of viewers saw and heard, especially during the debate's opening minutes, will likely become fodder for Republican attack ads to fuel the narrative that Biden is too old to hold office.

As the debate progressed, Biden appeared more in command of the facts, in the face of a stream of falsehoods from Trump, but that may not have been enough to overcome concerns among Democrats over his unsteady delivery.

Going into the debate, the pressure on Biden had been to disprove Republican claims that he was slipping because of his age. His campaign will now have to figure out how to recover amid calls among some Democrats for Biden to be replaced as the party's nominee for the Nov. 5 election.

BAD BLOOD

The animosity between the candidates frequently spilled into the open as the two men got personal. Each suggested the other was a criminal.

"The only person on this stage who is a convicted felon is the man I'm looking at right now," Biden said and then accused Trump of having sex with porn star Stormy Daniels.

"You have the morals of an alley cat," Biden said.

The bad blood was on display from the start when they eschewed the traditional handshake and did not acknowledge each other when they walked onto the stage. Biden frequently referred to Trump as "this guy" and chuckled at some of his opponent's more hyperbolic statements.

Near the end of the debate, Biden cast doubt on Trump's true height and weight, suggesting his opponent lied about both. Trump meanwhile boasted of his cognitive and physical health and noted he had won two championships at his golf club.

By contrast, he said, Biden "can't hit the ball 50 yards."

Biden immediately challenged Trump to a golf match, but only if Trump would carry his own bag.

"Let's not act like children," Trump responded.

SPARRING OVER THE ECONOMY

Both candidates tried to defend their performance on the key issue of the race for voters: the economy.

It is a tricky issue for Biden as an incumbent presiding over the economy at a time when voters are angry over higher food and gas prices.

Biden's approach was to blame Trump. The ex-president, he said, left him a "terrible" economy. He said he was working to bring down inflation.

Trump replied that inflation was "absolutely killing us" and accused Biden of doing nothing.

Voters, right now, seem to be agreeing more with Trump than Biden, with polls showing they favor Trump's handling of the economy. Registered U.S. voters favor Trump on the issue 43% to 37%, according to Reuters/Ipsos polling this month.

Biden's challenge on Thursday was to make clear to viewers that his administration is the one that dug the country out of the pandemic-induced hole.

"There was no inflation when I became president. You know why? The economy was flat on its back," Biden said.

LOSING HIS TRAIN OF THOUGHT

Biden seemed to lose his train of thought while responding to a question about the national debt.

His voice trailing off several times, Biden first referred to "billionaires" as "trillionaires" before correcting himself.

Then, while arguing that the wealthy should pay more tax, he seemed unable to complete his sentence, pausing for an extended awkward moment, before ending his thought in a way that sounded nonsensical.

Tax reform would create money to help "strengthen our healthcare system, making sure that we're able to make every single solitary person eligible for what I was able to do with the, with the COVID, excuse me, with dealing with everything we had to do with," Biden said before pausing.

"We finally beat Medicare," Biden said, likely referring to COVID-19.

Trump pounced.

"He's right. He did beat Medicare. He beat it to death."

BLACK VOTERS

Black voters' views - whether excitement, disappointment or apathy - may help decide the election.

They have voted overwhelmingly for Democrats in the past, but both candidates used the debate held in Atlanta, a heavily Black city in the swing state of Georgia, to make their pitch.

"I don't blame (Black voters)," Biden said, "for being disappointed. Inflation is still hurting them badly." But he said he was pushing for first-time home buyer tax credits and student loan forgiveness that could ease their cost of living.

Trump ripped into Biden and said he was picking up support from African-Americans who have been hurt by inflation.

"He lost much of the Black population because he's done a horrible job for Black families," Trump said.