Sen. Elizabeth Warren Elizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE (D-Mass.) leads the Democratic primary field by 4 points in the latest Economist/YouGov weekly tracking survey, leapfrogging former Vice President Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE as she continues to enjoy a boost in the polls.

Twenty-six percent of respondents who say they will vote in their Democratic presidential primary or caucus said Warren is their first choice, a 1-point bump from last week’s survey, while 22 percent said the same for Biden, down from 25 percent last week.

Sen. Bernie Sanders Bernie SandersSirota reacts to report of harassment, doxing by Harris supporters Republicans not immune to the malady that hobbled Democrats The Hill's Morning Report - Sponsored by Facebook - Republicans lawmakers rebuke Trump on election MORE (I-Vt.) was the only other candidate to register double digit support, at 14 percent, while South Bend, Ind., Mayor Pete Buttigieg Pete ButtigiegBillionaire who donated to Trump in 2016 donates to Biden The Hill's Morning Report - Sponsored by Facebook - GOP closes ranks to fill SCOTUS vacancy by November Buttigieg stands in as Pence for Harris's debate practice MORE and Sen. Kamala Harris Kamala HarrisTexas Democratic official urges Biden to visit state: 'I thought he had his own plane' The Hill's Campaign Report: Biden on Trump: 'He'll leave' l GOP laywers brush off Trump's election remarks l Obama's endorsements A game theorist's advice to President Trump on filling the Supreme Court seat MORE (D-Calif.) rounded out the top five at 7 percent and 5 percent, respectively.

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Warren topped the poll in part by chewing into key demographics for Biden and Sanders. The Massachusetts lawmaker cut her deficit on Biden to 2 points among voters aged 65 years and older and is only behind Sanders by 3 points among voters aged 18-29. She also leads among white voters with 31 percent support, compared to 18 percent for Biden and 13 percent for Sanders.

Warren also edges out Biden by 5 points among self-identified Democrats, 28 percent to 23 percent, though the poll shows a stiff competition for independents, with both Warren and Biden coming in at 20 percent and Sanders getting 18 percent among such voters.

However, she still struggles with voters of color, trailing Biden by a 36-15 percent margin among black voters and by a 22-17 percent margin among Hispanics.

Wednesday's survey matches similar polling that has signaled a new division within the primary field, with Warren, Biden and Sanders making up its top tier while relegating candidates like Harris, Buttigieg and others to its middle tier.

The Economist/YouGov poll surveyed 1,087 registered voters from Sept. 28-Oct. 1 and has a margin of error of 3.1 percentage points.

Chris Mills Rodrigo contributed to this report