Grady Diangana's first half strike was cancelled out by two Brighton goals in the final 15 minutes of Friday night's Premier League 2 clash as West Ham United's U23s travelled back from the south coast empty handed.
The visitors were the better team for large chunks of the Amex Stadium fixture, but ultimately paid the price for spurning a number of opportunities to increase their advantage.
The Hammers now turn their attention to Tuesday night's opening Checkatrade Trophy tie at Bristol Rovers.