Even the most carefully constructed campaigns must reckon with humbling afternoons. Arsenal, defending Premier League champions and unbeaten through nine league matches, were dismantled 3-0 by Brighton on Saturday — their heaviest defeat since first claiming the title in 1989. Manager Mikel Arteta called it a 'big lesson,' a phrase that acknowledges what sport has always known: dominance is never permanent, and the game has a way of restoring its own balance.