It was Brighton's first away win in the top flight since 1983 as the Hammers were booed off by their furious fans with the club slipping down to 17th in the Premier League table at the quarter way stage of the season.
And they could slip into the danger zone depending on other results this weekend.
Bilic's future has been in doubt since last season with supporters slowly turning on the Croatian for the club's lacklustre displays.
And the pressure looks like it is starting to take its toll after Bilic offered up the most ridiculous excuse for West Ham's struggles at the London Stadium BEFORE their latest defeat.
Speaking in his column in the Evening Standard on Friday Bilic said one of the reasons West Ham have struggled at home is the colour of the astroturf around the pitch.
"We have a great stadium but we want to improve it even more, to make it like, for example, the Parc des Princes, home of Paris Saint-Germain," Bilic said in the ES.
"If you look at their stadium, they have changed the colour of the area around their pitch to blue. We want to do something similar and change to a darker colour - claret.
"Let me explain it like this. It is impossible to bring the crowd closer but we can improve things by changing the perspective. Imagine you are a player, you are running back to defend or you are joining the attack - you look up and it is not easy, because everything is green ahead of you, to appreciate exactly where is the end of the pitch and that can psychologically affect your willingness to do it.
"We have done everything we can to receive permission to do this, especially our vice chairman Karren Brady. I am mentioning it almost every time I meet her."
In what will surely go down as one of the worst excuses ever heard from a football manager, it could be the final insult for fed up fans who are calling for change in the dugout and the boardroom.
Supporters are sick of hearing the stadium used as an excuse with many pointing to the fact away teams are not struggling to perform there regardless of the size of the pitch, distance from the stands or colour of the carpet.
The once enthusiastic, exciting and brave Bilic has lost his mojo and the owners will surely sense the fact he is now clutching at straws.