Latest poll shows a dead heat. In fact, even if McConnell pulls it out, there is a good chance he will no longer be Senate Majority Leader. Going by the latest poll in every race, it would be Democrats 51 Republicans 47 with Montana and Kentucky even.
https://projects.fivethirtyeight.com/polls/senate/kentucky/
Those polls are pretty old. It's hard to get reliable sampling in Kentucky. And I don't think Change Research is non-partisan anyway or even the other poll listed.
In a presidential year where Trump will win the state handily, that'll boost Mitch. Dem turnout will be higher in Louisville/Lexington but I don't see McConnell performing as badly as Bevin did (and Bevin only lost by 5,000 votes despite his disapproval ratings).