US President Joe Biden has said he thinks he would have defeated Donald Trump and won re-election in November.

Speaking to USA Today in an exclusive interview, Biden did, however, add that he was unsure if he would have had the stamina for another four-year term.

"So far, so good," the 82-year-old said. "But who knows what I'm going to be when I'm 86 years old?"

In the wide-ranging interview with Susan Page, Biden also said he was still considering pre-emptive pardons for foes of Donald Trump, including former Republican congresswoman Liz Cheney and former senior health official Dr Anthony Fauci.

In the interview published on Wednesday, Biden said he had been "very straightforward with Trump" about the potential pardons during their Oval Office meeting shortly after the November election.

"I tried to make it clear that there was no need, and it was counterintuitive for his interest to go back and try to settle scores," Biden said, adding Trump did not push back, but "just basically listened".

Biden said his ultimate decision will depend on who Trump selects for his cabinet.

At that same meeting, Biden said Trump was "complimentary" about his economic record.

"He [Trump] thought I was leaving with a good record," the Democrat said.

The interview with USA Today is the only exit interview Biden has so far given to a print publication.

Media access to Biden has been strictly controlled by the White House - and the president has not held a news conference since he dropped out of the race on 21 July.

In the interview, the outgoing president also defended the full and unconditional pardon he issued to his son, Hunter Biden, who was facing sentencing for two criminal cases - tax evasion and illegally buying a gun - despite repeatedly insisting he would not do so.

Biden, who first came to Capitol Hill in 1972 as a US senator, drew criticism from his own party over his apparent reluctance to drop out of the presidential race amid concerns over his age and mental acuity.

Speaking to USA Today, Biden said "based on polling" he believed he would have won, but conceded his age may have affected him in office.

"When Trump was running again for re-election, I really thought I had the best chance of beating him. But I also wasn't looking to be president when I was 85 years old, 86 years old," Biden said. "But I don't know. Who the hell knows?"

Following Vice-President Kamala Harris' loss to Trump, high-ranking members of the Democratic party, such as former House Speaker Nancy Pelosi, have said the Democrats might have fared better in the election had Biden exited the race sooner.