A new poll commissioned by Democrat Sean Casten’s congressional campaign finds U.S. Rep. Peter Roskam, R-Ill., under water for the first time in a hotly contested race.

The poll, conducted by the Garin Hart Yang Research Group on behalf of Casten’s campaign, finds Casten ahead 47 to 44 percent, with 9 percent undecided. The poll was taken Sept. 8-10 of 402 likely voters in Illinois’ 6th Congressional District, which covers suburbs in Cook, Lake, Kane, McHenry and Dupage counties. The margin of error is plus or minus 4.9 percentage points.

Casten’s campaign framed the poll as proof that Roskam’s spending in the race isn’t working. The campaign released a summary of its findings but not all the data collected. The poll also found 39 percent of voters had an unfavorable view of Roskam, with 33 percent of voters saying they had a favorable view.

Roskam has been forced to defend his record on President Donald Trump’s policies, and he’s fighting to keep his seat in a district that Democrat Hillary Clinton won by 7 percentage points in 2016. Casten — who beat out six other Democrats in the primary — is hoping a “blue wave” will give him enough momentum, and cash, to surge his campaign forward.

The poll also asked voters about Trump. Poll takers said that “nearly three in five voters,” or 58 percent, viewed Trump negatively in the district, which they claim is the worst ratings recorded for Trump since they began polling in the district.

Casten in April commissioned a poll which showed Roskam ahead 45 to 44 percent, with the same margin of error.

The Roskam campaign downplayed the latest poll.

“Everyone knows this race is close, but as 6th district voters learn about Sean Casten’s alliance with Mike Madigan to oppose the property tax freeze and repeal the recent middle-class tax cuts, that he was sued by his own investors for mismanagement, and that he lobbied for special tax credits and taxpayer subsidies to prop up his own businesses, we are confident voters will stick with Peter Roskam who has been an effective leader for Illinois and is rated as one of the most bipartisan members of Congress,” Roskam campaign spokeswoman Veronica Vera said in a statement.

The race between Roskam, who has held the seat since 2007, and Casten, a political newcomer and a former energy company executive, is under a microscope nationally as Democrats try to regain control of the chamber.

Roskam had about $2.3 million cash on hand at the end of June, Federal Election Commission reports show. He has spent $2.2 million. For that same time period, Casten had raised about $791,000 and and had $646,749 cash on hand.

In a July debate, Casten argued that the west suburban 6th Congressional District should be represented by someone who supports abortion rights and the middle class and opposes Trump.

The last major poll conducted in the race was on Sept. 7 by the New York Times. That poll also had a large margin of error. In that poll, Roskam led Casten 45 to 44 with 11 percent undecided.