One of the things about American politics that looks very odd from a British perspective is that each of the 50 states can have very different election rules for what is the same national contest.
So in the state of Georgia nobody can win an election unless they come out with 50% or more of the vote. This means that if no candidate achieves that threshold there has to be a runoff election 4 weeks later which is what is happening in the Senate race currently.
The contest is far less important than it might have been as was being speculated on the night when the results were coming in 3 weeks ago. At one stage it looks as though the control of the Senate would not be resolved until the Georgia runoff had taken place. As it turned out the Democrats made the gain of the Pennsylvania senate seat and achieved control
As can be seen from the polling table above the Georgia contest remains extremely close although punters have made the Democrats the odds on favourite.
The big question is whether the parties will be able to replicate the turn out that they had in the state on November 8th or whether it will be somewhat less in which case the outcome could be uncertain.