Joe Biden has edged into a three-point lead in the pivotal state of Texas, according to a new poll, raising the possibility that he could clinch the presidency on election night.
With minimal mail-in voting, the fate of Texas - and its 38 electoral college votes - is expected to be declared on November 3.
Should Mr Biden become the first Democrat presidential candidate to win the state since Jimmy Carter in 1976, Donald Trump's chances of retaining the Oval Office could be dealt a fatal blow.
Influential Texas Democrats including Beto O'Rourke, the former presidential candidate, have urged the party to pour resources into the state.
They argue that victory would put Mr Biden on course for the White House on November 3 irrespective of results in Wisconsin, Pennsylvania, Michigan, Ohio, North Carolina, Arizona and Florida.
Significantly, 40pc of those surveyed had already cast their ballot, reflecting a nationwide trend which has seen a surge in early voting with people queuing for hours at polling stations.
According to the latest figures, at least 56 million people have already voted - either by post or in person - because of the coronavirus pandemic, which has claimed 225,000 lives in the US.
The surge in early voting suggests the US could be on course for a record turnout of around 150 million people - representing 65pc of the electorate, a proportion unseen since 1908.
With 29 electoral votes, Florida is another pivotal state in the election.
Mr Trump, who won the state by 113,000 votes in 2016, is running neck and neck with Mr Biden this year according to the latest polls. They are also tied in Georgia and Mr Biden is narrowly ahead in North Carolina. The former vice-president will be hoping to reap the benefit of an advertising blitz, which has seen him spend $582m (€491m) on television slots - a new record for a presidential candidate.
Undeterred, Mr Trump, who defied expectations and the polls in 2016, is hurtling around the US making his case to voters in person.
Over the weekend the president held rallies in five states - North Carolina, Ohio, Wisconsin, New Hampshire and Maine.
He will be on the road every day until the election with events planned for Pennsylvania today, before moving on to Michigan, Wisconsin and Nebraska tomorrow.
Mr Biden, who addressed a rally in Pennsylvania over the weekend, has been more cautious with in-person campaigning, arguing that he does not want to be responsible for 'super spreader' events.
Yesterday Mr Biden attended mass near his home with two of his granddaughters, and later joined Kamala Harris, his running mate, for an "I will vote" concert.
This involved performances from an array of stars including Jon Bon Jovi, John Legend, the Foo Fighters and Cher.
Meanwhile, Mr Trump has voiced optimism about his own electoral prospects.
According to the Washington Post, he told donors last week that he thought it would be tough for the Republicans to keep control of the Senate.
He is on course to cement conservatives' grip on the Supreme Court with Amy Coney Barrett's nomination due to be confirmed by the Senate today. (© Daily Telegraph, London)