Since an identical poll was conducted at the end of September, Wilson has gained 10 percentage points and Blasdel has lost 9 percentage points, according to the poll of 800 registered voters from the district.

The Blasdel camp shrugged off the latest numbers. "[SurveyUSA] is all over the place with their numbers, and their results are not echoed in our internal polls," says Ryan Stenger, Blasdel's campaign manager. "The race is tightening up."

Stenger says that the key to the race will be independent voters, who can be wooed in the last three weeks before Election Day.

But Blasdel's support among independents is crumbling fast, the new poll shows: Independents now favor Wilson by 44 percentage points, which represents a 51-point swing from three weeks ago, when they favored Blasdel by 7 points.

—Alex Kingsbury