Arsenal and Everton claimed local superiority on a bumper Sunday of Women's Super League action.
The third-placed Gunners triumphed 2-0 over Tottenham in the competition's first north London derby - in front of a record WSL crowd of 38,262 - thanks to goals from Kim Little and Vivianne Miedema.
Spurs, in their first top-flight campaign, held out until the 66th minute until Little struck for the champions with a fine left-footed drive and Miedema then secured the points eight minutes from time.
On the first designated Women's Football Weekend - taking advantage of the break in the Premier League and Championship calendar - the crowd at the Tottenham Hotspur Stadium surpassed the 31,213 at Manchester City for the visit of Manchester United on the opening weekend of the season in September.
Everton's helping hand in Merseyside derby
The day's other big derby came at Anfield - 23,500 in attendance there - but Liverpool suffered a 1-0 defeat to Everton.
A howler from Reds goalkeeper Anke Preuss proved decisive in the first WSL Merseyside derby to be held at the stadium as Willie Kirk's side, in winning at their neighbours' ground, did what their male counterparts have not been able to do since 1999.
The hosts - bottom of the table - were in fact the better side for much of the afternoon, with Kirsty Linnett and Niamh Charles particularly influential, but Preuss let Lucy Graham's shot slip through her grasp just before the interval and that was enough for Everton to leapfrog Manchester United into fourth place.
Man City hit five, Chelsea climb back to summit
Manchester City's Georgia Stanway had an eventful afternoon, scoring twice in the first half and getting sent off in the second for two yellow cards as her side thrashed West Ham United 5-0 at the Academy Stadium to briefly top the table.
City were the pacesetters for about an hour until Chelsea's Maren Mjelde converted a second-half penalty to secure a 1-0 win at home to Manchester United.
The victory put the Londoners back in pole position on 16 points after six games, one ahead of City and Arsenal, who are third on goal difference.
Elsewhere, Reading's stuttering season continued as they threw away a 3-1 lead against Bristol City, who fought back to draw 3-3, while Brighton & Hove Albion beat visiting Birmingham City 3-0 to notch their first win of the season.