Sen. Elizabeth Warren gained ground as support for Joe Biden, Sen. Bernie Sanders and Sen. Kamala Harris slipped in a new poll released on Sunday.

The four remain at the top of the Democratic presidential heap leading into this Thursday’s debate in Houston, the ABC/Washington Post survey found.

The former vice president leads the pack with 27 percent of support from Democrats and Democrat-leaning independents, but that’s down 2 percentage points from the survey’s results in July 1.

Sanders fell to 19 percent from 23 percent in July, while Harris toppled to 7 percent from 11 percent.

But Warren saw her level of support shoot up to 17 percent from 11 percent.

The remainder of the Democratic field are in the single digits, including Pete Buttigieg at 4 percent, and Beto O’Rourke and Andrew Yang tied at 3 percent.

The rest were at 1 percent or less.

The survey polled 1,003 adults between Sept. 2 and Sept. 5. It has a plus/minus 5.5 percentage point margin of error.