The Women's Super League London derby ended with a controversial decision which decided the outcome of the game.
The game had been a tight fixture but in the 84th minute referee Emily Heaslip gave Chelsea a penalty. Lauren James made a run into the box and Kim Little tackled her which saw James trip.
From the referee's angle she believed Little did not get any of the ball and awarded a penalty. Guro Reiten stepped up and scored to see the Blues do the double over their London rivals in the WSL this season.
London derby: Why isn't there VAR in the WSL?
Replays in slow motion seems to show Little getting the ball before she made contact with James.
Arsenal players protested but Heaslip stuck with her decision. The referee could not review the incident as VAR is not in use in the WSL.
The technology is not used in the English women's top-flight mainly because the large majority of home grounds cannot support the technology. Financial constraints are also a factor with a large portion of referees in the WSL not full-time.
Sticking with her decision, Heaslip copped some criticism from Arsenal's Katie McCabe.
McCabe was seen having words with the referee which resulted in her receiving a straight red card.
There has not been confirmation if McCabe will miss the next game but a player is usually suspended for the next fixture.
The penalty meant Chelsea won the game 1-0 to maintain their unbeaten run in the league this season. In FourFourTwo's view, the Blues will win the WSL title for a sixth season in a row this campaign.
The Blues are top of the table, seven points clear of second-place Manchester United.
The loss for Arsenal mean they are fourth and 10 points behind Chelsea. The defeat was also manager Renee Slegers' first loss since she took over from Jonas Eidevall in October.
