Nayef Aguerd, Michail Antonio and Lucas Paqueta struck as West Ham earned a memorable 3-1 home win over Chelsea at the London Stadium.
Aguerd put the Hammers ahead in the seventh minute by heading home James Ward-Prowse's corner, only for Chelsea to equalise through Carney Chukwuemeka.
Enzo Fernandez passed up the chance to put a dominant Chelsea side ahead in the first half after seeing his penalty saved by Alphonse Areola.
The miss proved costly when Antonio sent a powerful drive beyond Robert Sanchez in the early stages of the second half.