There ARE some larger red counties, like Cherokee, with a lot of votes yet to report.
Walker was actually leading for just a few seconds there when it was at 86% of the vote counted. They fixed that right quick though and it is now 87% in and Warnock in the lead by 16,000.
Cherokee is large for a red county, but is only slightly less in than the state as a whole, and only has about 17k votes left—the top four outstanding dem counties eash have 4-7 times that number.