Graham Potter endured a nightmare return to Amex Stadium as Brighton thrashed Chelsea to claim a first victory under their new manager Roberto de Zerbi.
In a chaotic opening, Leandro Trossard’s calm finish put the home side in front after Thiago Silva – who had already produced two goalline clearances to deny the Seagulls – surrendered possession cheaply in his own half.
Two own goals extended Brighton’s lead before the break, Ruben Loftus-Cheek putting through his own net from a Solly March corner before Trevoh Chalobah slid Pervis Estupinan’s low cross past Kepa Arrizabalaga.
Kai Havertz nodded in Conor Gallagher’s exquisite cross to give the visitors hope two minutes after the interval, but a second-half Chelsea recovery failed to materialise.
Pascal Gross capped a miserable afternoon for Potter and his players with a close-range finish in second-half stoppage time.
The victory lifts De Zerbi’s side up to seventh, while Chelsea stay fifth after suffering their first defeat of Potter’s tenure.
