"The Senate race looks like it will go down to the wire on Election Day," said Peter A. Brown, assistant director of the Quinnipiac University Polling Institute, in a statement. "With 10 percent of voters undecided, each man has the opportunity to win the seat."

Still, neither candidate has ever broken beyond the margin of error since the polling firm began surveying the state, further emphasizing the even split between the two heavyweights.

That could mean that presidential efforts in the state — already expected to be intense, with 13 electoral votes squarely up for grabs and Mitt Romney's campaign acknowledging that any path to the Oval Office will likely lead through Virginia — carry even more significance.

"The Senate race is so close that whatever small margin of victory occurs could well be based on whether President Barack ObamaBarack Hussein ObamaTrump adds to legal team after attacks on Mueller Stock market is in an election year: Will your vote impact your money? Trump will perpetuate bailouts by signing bank reform bill MORE or Gov. Mitt Romney has coattails," said Brown.

Allen might also have to grapple with slipping popularity for incumbent Gov. Bob McDonnell, whose job approval rating slipped to match his all-time low in the survey. Still, McDonnell remains quite popular in the state, with more than half of Virginians approving of the job he's doing as governor.