Alessia Russo scored the only goal of the game as Arsenal overcame local rivals Tottenham in front of a sellout crowd at Emirates Stadium.
The England striker smashed the ball home from close range early in the second half after Kim Little and Beth Mead combined to create the chance.
Victory keeps Arsenal firmly in the Women’s Super League title race, three points behind leaders Manchester City.
Tottenham stay sixth as their winless run extends to four games
