Match ends, Chelsea Women 2, Arsenal Women 1.
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.
- 10JiBooked at 38minsSubstituted forSpenceat 83'minutes
- 11ReitenSubstituted forThorisdottirat 74'minutes
- 14KirbySubstituted forBachmannat 75'minutes
- 13WältiSubstituted forNobbsat 64'minutes
- 7van de Donk
- 23MeadBooked at 45mins
- 11MiedemaBooked at 40mins
- Rebecca Welch
- Shots on Target
Second Half ends, Chelsea Women 2, Arsenal Women 1.
Foul by Daniëlle van de Donk (Arsenal Women).
Ann-Katrin Berger (Chelsea Women) wins a free kick in the defensive half.
Corner, Arsenal Women. Conceded by Erin Cuthbert.
Offside, Arsenal Women. Jill Roord tries a through ball, but Kim Little is caught offside.
Jennifer Beattie (Arsenal Women) wins a free kick in the defensive half.
Foul by Drew Spence (Chelsea Women).
Attempt saved. Beth Mead (Arsenal Women) left footed shot from the right side of the box is saved in the centre of the goal. Assisted by Daniëlle van de Donk.
Kim Little (Arsenal Women) wins a free kick in the attacking half.
Foul by Sophie Ingle (Chelsea Women).
Goal! Chelsea Women 2, Arsenal Women 1. Maria Thorisdottir (Chelsea Women) right footed shot from outside the box to the bottom right corner. Assisted by Ramona Bachmann.
Substitution, Chelsea Women. Drew Spence replaces Ji So-Yun because of an injury.
Corner, Arsenal Women. Conceded by Jonna Andersson.
Attempt saved. Ramona Bachmann (Chelsea Women) right footed shot from outside the box is saved in the centre of the goal.
Attempt missed. Ji So-Yun (Chelsea Women) left footed shot from outside the box misses to the right. Assisted by Ramona Bachmann.
Offside, Chelsea Women. Beth England tries a through ball, but Ji So-Yun is caught offside.
Attempt missed. Ji So-Yun (Chelsea Women) header from a difficult angle on the left misses to the left. Assisted by Maren Mjelde with a cross.
Substitution, Chelsea Women. Ramona Bachmann replaces Francesca Kirby.
Substitution, Chelsea Women. Maria Thorisdottir replaces Guro Reiten.