It was "a huge opening weekend for former Vice President Joe Biden — think Avengers: Endgame here," CNN's John Berman said on Tuesday morning's New Day, introducing a new national poll that shows Biden taking a commanding lead in the 2020 Democratic field one day after officially joining the race.

In the CNN/SSRS poll, conducted April 25-29, Biden opened up a commanding lead in the 20-person Democratic field, grabbing 39 percent of Democrats and Democratic-leaning independents, more than double the support of his next-closest rival, Sen. Bernie Sanders (I-Vt.), at 15 percent. Next is Sen. Elizabeth Warren (D-Mass.) at 8 percent, followed by South Bend Mayor Pete Buttigieg at 7 percent, former Texas Rep. Beto O'Rourke at 6 percent, and Sen. Kamala Harris (D-Calif.) at 5 percent. Biden's support jumped 11 percentage points since the last CNN/SSRS poll, while Buttigieg jumped 6 points and everybody else lost ground.

NEW: Former Vice President Joe Biden's presidential announcement earned him an 11-point polling bounce in a new CNN poll, leaving him head and shoulders above the rest of the Democratic candidates. https://t.co/lPvN8W7T5F pic.twitter.com/2dszIbxHb1 — New Day (@NewDay) April 30, 2019

The top issue for Democrats and leaners was combating climate change, and the most important attribute for a candidate was ability to beat President Trump, the poll found. Biden's early message has focused on beating Trump. He leads the other 19 candidates among all major demographic groups, including half of non-white voters, but two-thirds of voters said they could still change their mind about which candidate they support. Biden's lead in the CNN poll is slightly larger than in Monday's Morning Consult tracking poll, which had Biden leading Sanders 36 percent to 22 percent; that poll was conducted April 22-28.

SSRS polled 1,007 adults nationwide over the phone, but the sample of 411 Democratic and Democratic-leaning independent registered voters has a margin or sampling error of ±5.9 percentage points. Peter Weber