Act Four opens with Hippolyte's monologue "Ah, faut-il qu'en un jour", which looks forward to similarly "elegiac" arias in Rameau's later operas, for example "Lieux désolés" in "Les Boréades". The "divertissement" in the middle of the act celebrates the hunt, with extensive use of horns. The finale is devoted to Hippolyte's confrontation with the sea monster, depicted in stormy music in which the flutes represent blasts of wind. It ends with Phèdre's great lament, which Sylvie Bouissou describes as "one of the finest pages of French Baroque opera".