Sen. Elizabeth WarrenElizabeth Ann WarrenBiden, Warren in dead heat in New Hampshire: poll Hillicon Valley: Court largely upholds FCC's net neutrality repeal | Warren blasts Zuckerberg over leaked audio | DNC accuses Facebook of letting Trump 'mislead' public | UPS gets approval for drone delivery Trump campaign, RNC raise staggering 5 million in third quarter MORE (D-Mass.) leads the Democratic primary field by 4 points in the latest Economist/YouGov weekly tracking survey, leapfrogging former Vice President Joe BidenJoe BidenHarris presses Twitter to 'do something' over Trump's 'coup' tweet Poll: 40 percent of Republicans say Trump 'probably' mentioned Biden on Ukraine call Pompeo, House chairmen clash in impeachment fight 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 SandersBernie SandersBiden, Warren in dead heat in New Hampshire: poll Trump campaign, RNC raise staggering 5 million in third quarter Biden has 20-point lead in South Carolina primary: poll MORE (I-Vt.) was the only other candidate to register double digit support at 14 percent, while South Bend, Ind., Mayor Pete ButtigiegPeter (Pete) Paul ButtigiegBiden, Warren in dead heat in New Hampshire: poll Trump campaign, RNC raise staggering 5 million in third quarter Biden has 20-point lead in South Carolina primary: poll MORE and Sen. Kamala HarrisKamala Devi HarrisHarris presses Twitter to 'do something' over Trump's 'coup' tweet Biden, Warren in dead heat in New Hampshire: poll Trump campaign, RNC raise staggering 5 million in third quarter MORE (D-Calif.) rounded out the top five at 7 percent and 5 percent, respectively.

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,  or by 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 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 percent.

Chris Mills Rodrigo contributed to this report