Brighton earned just a fourth win of 2024.
Cole Palmer, Conor Gallagher, Noni Madueke and Nicolas Jackson (two) were on target as the Hammers were crushed.
Brighton 1-0 Aston Villa: The hosts ended a six-game winless run to stall Villa’s top-four hopes
Chelsea 5-0 West Ham: Nicolas Jackson scored twice after first-half goals from Cole Palmer, Conor Gallagher and Noni Madueke