There were quite a few firsts at the AMEX. It was Graham Potter's first defeat in charge of Chelsea. It was Roberto De Zerbi's first win in charge of Brighton. It was Brighton's first win over Chelsea in the league. It was Trevoh Chalobah's first defeat when starting as a Chelsea player.
Though all that said, there was a tinge of familiarity about this particular Chelsea collapse.
As Leandro Trossard put in the first, then Ruben Loftus-Cheek added to the deficit by putting through his own net, only for his academy peer Chalobah to do the same, you could flip back through the disasters on the road across the past five years.