  The $n$-dimensional random twisted hypercube $\mathbf{G}_n$ is constructed
recursively by taking two instances of $\mathbf{G}_{n-1}$, with any joint
distribution, and adding a random perfect matching between their vertex sets.
Benjamini, Dikstein, Gross, and Zhukovskii showed that its diameter is $O(n\log
\log \log n/\log \log n)$ with high probability and at least ${(n - 1)/ \log_2
n}$. We improve their upper bound by showing that
$$\operatorname{diam}(\mathbf{G}_n) = \big(1 + o(1)\big) \frac{n}{\log_2 n}$$
with high probability.
