A tensor defined over a finite field F has low analytic rank if the distribution of its values differs significantly from the uniform distribution. An order d tensor has partition rank 1 if it can be written as a product of two tensors of order less than d, and it has partition rank at most k if it can be written as a sum of k tensors of partition rank 1. In this paper, we prove that if the analytic rank of an order d tensor is at most r, then its partition rank is at most f (r, d, |F|), where, for fixed d and F, f is a polynomial in r. This is an improvement of a recent result of the author, where he obtained a tower-type bound. Prior to our work, the best known bound was an Ackermann-type function in r and d, though it did not depend on F. It follows from our results that a biased polynomial has low rank; there too we obtain a polynomial dependence improving the previously known Ackermann-type bound.A similar polynomial bound for the partition rank was obtained independently and simultaneously by Milićević.