The tone for Chelsea's afternoon of sloppy defending was set just seven minutes in at the London Stadium, when Nayef Aguerd was given all the space in the world to nod home a corner from West Ham debutant James Ward-Prowse.
The hosts' second goal reflected just as poorly on Mauricio Pochettino's side, as a comedy of errors led to Michail Antonio nearly taking the net off with a powerful strike eight minutes after the break. The cherry on top of a farcical cake came when £115 million ($146m) signing Moises Caicedo conceded a late penalty in the dying embers, lazily bringing Emerson down, with Lucas Paqueta converting from the spot to seal a 3-1 win.
As much as this will have frustrated Pochettino, there were at least some signs of life going forward - something that was desperately lacking for pretty much the entirety of the 2022-23 season.
Carney Chukwuemeka's goal was sublime, Raheem Sterling was unplayable at times and his side peppered Alphonse Areola's goal. If Enzo Fernandez could have scored his penalty, or the Blues could have shown a little more composure when West Ham were reduced to ten me after Aguerd's red card, they likely would have come away from east London with something.
Instead, they head back across the capital with the sour taste of defeat in their mouths - with Pochettino still awaiting his first three points as Blues boss. The footballing revolution he was tipped to bring certainly hasn't started yet.
GOAL rates Chelsea's players from the London Stadium...