Graham Potter suffered defeat for the first time as Chelsea boss

Potter had been unbeaten in his first nine games since leaving Brighton to take over at Chelsea last month.

By contrast, the Seagulls had not won in their first five games under new boss Roberto De Zerbi, but that all changed in a dominant first half by Brighton.

Nine-game Chelsea winning run poetically came to an end against former club Brighton and it was his tactics that were to blame for a 4-1 thumping on the south coast.

The Blues lined up in the same 3-5-2 shape that had helped them win away at RB Salzburg in the Champions League in midweek.

Chelsea were evidently happy with how it worked in Austria, where they ran out 2-1 winners, but here they found themselves 3-0 down against Roberto De Zerbi’s side by half-time.

Thiago Silva twice cleared off the Chelsea goal line in the first five minutes before Leandro Trossard fired home the opener.

A Solly March corner was then inadvertently turned in off the underside of the crossbar by Ruben Loftus-Cheek, giving the visitors a mountain to climb.

Shell-shocked, Chelsea searched for a response but a second own-goal on the stroke of HT all but sealed the points for the Seagulls. Pervis Estupiñán raced down the left wing before squaring, persuading Trevoh Chalobah to slide in and unwittingly turn the ball past Kepa.

Kai Havertz had scored three goals for Chelsea this season, each coming after the break, and right on cue, the German delivered another. Conor Gallagher whipped in a dangerous ball to the far post after good work from Loftus-Cheek, leaving Havertz to head home and reignite Chelsea hope.

The Blues pushed hard for a second goal, but Brighton held firm, and capped off a dream afternoon with a stoppage-time goal from Pascal Gross to claim a first H2H win since 1933 when these sides met for the first time. As for Chelsea, the demoralising defeat leaves them fifth in the Premier League, just three points ahead of Brighton in seventh.