Donald Trump has acknowledged that his US presidential campaign faces challenges and could ultimately fall short.
It was a rare show of humility as the boastful billionaire strayed from his signature bravado in the battleground state of Florida.
The Republican presidential nominee told a gathering of evangelical ministers on Thursday that he's "having a tremendous problem in Utah".
The same day, the reality show star acknowledged that his lack of political correctness could cost him the election if Americans reject his blunt approach.
"We're having a problem," Mr Trump told the ministers, adding that the next president could get to nominate up to five high-court justices. "It could cost us the Supreme Court."
After trouncing 16 challengers in the Republican primary, Mr Trump is encountering worrying signs as his campaign moves into the general election.
Democrat Hillary Clinton's lead over him in national polls has widened in recent days, while a growing number of fellow Republicans have declared they will not support their own party's nominee.
Mr Trump's exercise in self-awareness is a marked departure from his usual tenor on the campaign trail, where for months at rallies he would tick through poll numbers showing him winning as if they were sports scores of his favourite team.
"We're going to win so big," he told a roaring crowd at the Republican National Convention a month ago.
Yet on Thursday, he was reduced to citing a poll that actually showed him a few points behind Mrs Clinton and arguing that the race between them was close.
Asked how he planned to reverse her advantage, Mr Trump said he simply planned to do "the same thing I'm doing right now".
"At the end, it's either going to work, or I'm going to, you know, I'm going to have a very, very nice, long vacation," he told CNBC.
Even while working to restore confidence in his campaign, Mr Trump appeared to court fresh controversy when he said late on Thursday that he was open to trying Americans suspected of terrorism at the Guantanamo Bay detention centre in Cuba.
Asked specifically about US citizens, he said he did not like that President Barack Obama and others wanted to try them in traditional courts rather than military commissions at Guantanamo Bay.
"I would say they could be tried there," Mr Trump said. "That'll be fine."
In Utah, typically a reliably Republican state, Mr Trump's challenges have been particularly striking. The state's large Mormon population has voiced serious scepticism about him, though the state's GOP governor has endorsed him.
"We've really been given a false narrative," Mr Trump said of his struggles in Utah.
Yet in other traditionally GOP-leaning states, like Arizona and Georgia, Republicans are concerned that Mr Trump's unpopularity could give Democrats an improbable victory.
Those concerns are compelling enough that dozens of worried Republicans gathered signatures on Thursday for a letter urging the GOP chairman to stop helping Mr Trump and focus on protecting vulnerable House and Senate candidates.
Mr Trump said he was not worried that Republicans would cut him off - and threatened to stop fundraising for the party if they do.
His campaign planned to sit down with RNC officials in Orlando on Friday. But both Republican Party officials and the Trump campaign said the meeting was focused on Florida campaign operations and not tensions between the campaign and the GOP.
Mr Trump's unusually candid reflections about the uncertainty of his electoral prospects come as he struggles to keep the focus on his opponent and avoid distractions.
Earlier this week he caused a major stir with comments about the Second Amendment which were perceived as advocating violence against Mrs Clinton, then faced questions yet again after declaring on Wednesday that President Obama was the "founder" of the Islamic State group - a patently false claim.
It is comments like those that Mrs Clinton has seized on to try to contrast her "serious, steady leadership" with the more volatile approach she says Mr Trump would take to running the country.
"I just do not think insults and bullying is how we are to get things done," she said as she laid out her economic plan in Warren, Michigan, on Thursday.