<p>We study the maximally supersymmetric Yang-Mills theory on <i>S</i>^<i>d</i> using supersymmetric localisation and holography. We argue that the analytic continuation in dimension to <i>d</i> = 1 yields a Euclidean version of the BMN matrix quantum mechanics. This system can be analysed at large <i>N</i> using supersymmetric localisation and leads to explicit results for the free energy on <i>S</i>^<i>d</i> and the expectation value of supersymmetric Wilson loops. We show how these results can be reproduced at strong gauge coupling using holography by employing spherical D-brane solutions. We construct these solutions for any value of <i>d</i> using an effective supergravity description and pay particular attention to the subtleties arising in the <i>d</i> → 1 limit. Our results have implications for the BMN matrix quantum mechanics and the physics of circular D0-branes.</p>