This is just about as close as it gets.
In the Republican primary for the US House in TN-4, the incumbent, Scott DesJarlais, has apparently defeated the challenger, Jim Tracy, in what turned out to be a very nasty campaign. But I say "apparently" because it is just too close to be entirely certain: With 100 percent of the precincts reporting, DesJarlais can claim 34,779 votes, whereas Tracy has 34,746. That is surely a razor-thin margin. (Thirty-three votes, to be exact.)
I would not be surprised to see the result challenged.