Probability that half the nodes has more than half out-degree

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This is something I just wondered about, and I don't know whether there is a closed-form answer or not. I've tried but without making progress, so any idea would be helpful.

Consider a complete graph with $2n$ nodes. Each edge $uv$ is assigned a direction $u\rightarrow v$ or $v\rightarrow u$, each with probability $1/2$. Let $k$ be the number of nodes whose out-degree is at least $n$ (i.e. it has an arrow to more than half of the remaining nodes.) What is the probability that $k=n$?