Maria Thorisdottir’s late strike earned a thrilling derby victory as Chelsea hit back to end Arsenal’s perfect start to the Women’s Super League season.
The Gunners led when Vivianne Miedema’s astute pass picked out Danielle van de Donk, whose shot found the far corner.
Chelsea deservedly levelled after the break, Beth England neatly turning the ball home from a Fran Kirby cut-back.
And substitute Thorisdottir curled in a stunning winner to take unbeaten Chelsea above Arsenal and into second.
Thorisdottir hit the ball first time from fellow sub Ramona Bachmann’s 85th-minute pass to ensure a third Blues league win in four and move them to within two points of leaders Manchester City.
There were some nervy moments for the hosts late against a Gunners side who had won their past 11 league games stretching back to last season.
But Chelsea just about held out and celebrated in raucous style in front of a crowd of 4,149 at the full-time whistle.
Van de Donk’s early goal was reward for a bright start by the champions in an open match, but Emma Hayes’ side gradually got on top.
Ji So-Yun fizzed a shot narrowly wide and a fierce long-range Guro Reiten shot came back off the bar.
The pressure told when Kirby scampered away and found England with a clever pass soon after the restart.
Both sides pressed for a winner and had chances, but it was the home side who took the points thanks to an unlikely source in defender Thorisdottir.