A stylish Arsenal moved back into pole position in the Premier League title race after beating Brighton, a victory that saw them leapfrog Liverpool and Manchester City.
Just hours after City had swatted Crystal Palace aside at Selhurst Park, the pressure was once again on Mikel Arteta's contenders to respond on the south coast.
An ice-cool first-half penalty from Bukayo Saka, awarded after Tariq Lamptey's dangling leg caught Gabriel Jesus, handed the visitors the lead at the interval.
They then doubled their advantage through Kai Havertz's poacher's finish shortly after the hour mark, before Leandro Trossard netted against his former club.