The rain gave Mercedes the chance to upend the form book after Ferrari appeared set for pole in the dry.
Hamilton headed team-mate Valtteri Bottas by 0.260 seconds, while title rival Sebastian Vettel could manage only fourth, behind Ferrari team-mate Kimi Raikkonen.
Hamilton headed team-mate Valtteri Bottas by 0.260 seconds, while title rival Sebastian Vettel could manage only fourth, behind Ferrari team-mate Kimi Raikkonen.
