The Clarus Research Group -- which is not aligned with any candidate -- said Gray leads Fenty 39 percent to 36 percent among all voters, with 20 percent undecided. That suggests the winner may be the candidate with the best ground game getting his voters to the polls.
Earlier independent polls had Gray farther ahead, suggesting Fenty and his $4 million campaign war chest is having an effect in whittling away Gray's advantage.
Both campaigns and political observers are awaiting a poll expected any day now from The Washington Post. It could give a definitive answer to just how close this race is going into the Sept. 14 Democratic primary.
But for the first time this year, citizens can cast ballots as early as Aug. 30 under a new law allowing early voting for two weeks. The Board of Elections believes as many as a third of the 100,000-plus voters will cast ballots before the actual primary day itself.
The Clarus poll says there is a significant racial divide in the District, with overwhelming white majorities supporting Fenty and significant black majorities supporting Gray.
On Wednesday, Gray and Fenty appeared on WAMU 88.5 radio -- a special "Politics Hour" with host Kojo Nnamdi and Tom Sherwood from NBC4. Both candidates disavowed allegations from some citizens that "racism" is playing a part in school reform decisions made by Schools Chancellor Michelle Rhee.
Fenty also released a new ad that almost apologizes for his abrasive personality that has become an issue in the race for mayor.
In the ad and on the radio, Fenty pledges to be more open to other ideas if he is elected to a second term. Gray has called that a political deathbed conversion that's not to be believed.