Former Democratic Gov. Phil Bredesen holds a 5-point edge over U.S. Rep. Marsha Blackburn in Tennessee's U.S. Senate race, according to a CNN poll released Monday.

The poll, conducted last week, found that 50 percent of likely voters plan to cast their ballot for Bredesen, while 45 percent currently back Blackburn, the Republican nominee. The poll found 1 percent of likely voters favored neither candidate and 3 percent had no opinion.

The two are campaigning to replace the retiring U.S. Sen. Bob Corker in the Nov. 6 general election.

Among likely voters who responded to the survey, 85 percent said their mind was made up and did not expect to change before Election Day.

The statewide poll of 723 likely Tennessee voters was conducted for CNN by SSRS, an independent research company from Sept. 11 to Sept. 15 using both landlines and mobile phones. It has a margin of error of plus or minus 4.3 percentage points.

The CNN survey also polled Tennesseans on their preference in the gubernatorial race, finding that Republican candidate Bill Lee holds a 9 percentage-point advantage over Democrat Karl Dean, the former Nashville mayor.

Lee had the support of 52 percent of likely voters to Dean's 43 percent.

A Fox News poll released last week found 47 percent of likely voters surveyed said they'd vote for Blackburn, compared to 44 percent for Bredesen.

In the same poll, 54 percent of likely voters said they had a favorable view of Bredesen to 51 percent with a positive view of Blackburn.

The CNN poll released Monday also found that the Democratic candidate held an advantage in Arizona's race for retiring U.S. Sen. Jeff Flake's seat, which, like Corker's, is critical in Democrats' efforts to take control of the U.S. Senate.

U.S. Rep. Kyrsten Sinema, a Democrat, is leading Republican U.S. Rep. Martha McSally by 7 points, 50 percent to 43 percent among likely voters.

Reach Natalie Allison at nallison@tennessean.com. Follow her on Twitter at @natalie_allison.