More polling evidence emerged this week that Sen. Elizabeth Warren of Massachusetts may be eclipsing Bernie Sanders for second place in the race for the Democratic presidential nomination — a development sure to rattle the already agitated campaign of the senator from Vermont.

A Fox News national poll released Thursday indicated that former Vice President Joe Biden remains the front-runner, at 31 percent. But the poll put Warren at 20 percent, doubling Sanders' standing of 10 percent.

FOX NEWS POLL: BIDEN STILL LEADS - WARREN CLIMBS INTO SECOND

And an average of the latest 2020 Democratic presidential nomination polls by aggregator Real Clear Politics now puts Warren at 17.3 percent, slightly ahead of Sanders at 16 percent. None of the other candidates in the record-setting field of some two-dozen White House contenders cracked double digits.

All of these polls were conducted after the second round of Democratic presidential primary debates — which were held two weeks ago. Political pundits and analysts gave Warren high marks for her performance on the debate stage.

Just as important: Warren now has a slight edge over Sanders (and Sen. Kamala Harris) in the Real Clear Politics average of the latest surveys in Iowa, the state that votes first in the presidential nominating calendar. But she trails Sanders by over 3 percentage points in an average of the most recent polls in New Hampshire, which holds the first presidential primary.

Both Warren and Sanders, the party’s two liberal standard-bearers, campaigned in New Hampshire this week. The state – which neighbors both Massachusetts and Vermont – is considered a ‘must win’ for both candidates.

In a moment that encapsulated her steady surge in recent months, a video shot by a CNN reporter of Warren running through a field of cheering supporters at an event at a farm in Franconia, N.H., with the scenic White Mountains as her backdrop, quickly went viral this week.

Like Warren, Sanders also drew healthy crowds during his latest campaign swing in the first-in-the-nation primary state.

But he was also fighting perceptions that his campaign is slipping.

“While you may not know it from recent media coverage, Bernie Sanders is on a positive trajectory in his campaign for president as evidenced by multiple data points,” his campaign argued in a memo released this week.

SANDERS AND HIS CAMPAIGN PUSH BACK AGAINST MEDIA

In a conference call with reporters, Sanders campaign pollster Ben Tulchin repeatedly emphasized that what he considered a flawed and negative media narrative that Sanders is slipping in the polls “is not true.”

Pointing to an analysis of public opinion surveys conducted following last month’s second round of Democratic primary debates by polling website FiveThirtyEight, Tulchin said that a “new independent polling analysis finds that Sanders has gained the most support of any candidate since the second round of debates and is solidly in second place among the field.”

Senior adviser Jeff Weaver specifically took aim at recent reports by CNN, MSNBC and The Washington Post.

Hours later, Sanders targeted both the Post and the New York Times for their coverage of his campaign.

SANDERS CLASHES WITH WASHINGTON POST

"I talk about (Amazon's taxes) all of the time," Sanders said at a town hall in New Hampshire. "And then I wonder why The Washington Post, which is owned by Jeff Bezos, who owns Amazon, doesn't write particularly good articles about me. I don't know why."

And he charged that the "New York Times is not much better” than the Washington Post when it comes to coverage of his presidential campaign.