Chelsea beat Arsenal 2-1 at the Emirates on Saturday to extend their perfect start to the Women's Super League season under new boss Sonia Bompastor.
Bompastor's predecessor Emma Hayes, now head coach of the United States women's national team, was in attendance as first-half goals from Mayra Ramírez and Sandy Baltimore proved enough to claim all three points in the London derby.
The result increases pressure on Arsenal boss Jonas Eidevall, whose team have now won just one of their opening four games in the WSL and were beaten 5-2 by Bayern Munich in the UEFA Women's Champions League earlier in the week.