Kai Havertz sure needed that! And so too did the Blues.
The German hadn't scored a Premier League goal since May 22 - but he ended his slump in the 88th minute Saturday by sweeping in a low Ben Chilwell cross in a powerful response to being dropped from the starting line-up.
Havertz was one of several usual first-team players left out, as Thomas Tuchel also benched Jorginho and Mason Mount after a disastrous mid-week defeat to Southampton.
It wasn't a perfect all-round showing by the Blues, but Tuchel will take it.
The Hammers found a breakthrough just after the hour mark, with Chelsea's calamitous defending giving them a helping hand. Once again, Tuchel's team failed to deal with a corner and the ball eventually broke for Michail Antonio to tap home.
Chilwell, brilliant off the bench, levelled the score soon after coming on. The wing-back took down Thiago Silva's long ball expertly and then nutmegged Lukasz Fabianski with a deft finish. He was involved in the winner too, setting up Havertz to be the hero in the final minutes of an intense second half.
West Ham then thought they had an equaliser, only for Maxwel Cornet's apparent goal to be controversially disallowed by VAR.