Chelsea and Arsenal both enjoyed 5-0 wins and Manchester City slumped to a 4-2 derby defeat to Manchester United as the Women's Super League saw some major changes at the top of the table after the competition resumed following the Christmas break.
Leaders Chelsea hammered West Ham Unitedand top the standings on 31 points from 11 games, seven ahead of Arsenal, who beat Crystal Palace to move up to second,and Manchester United, who moved past City and into third place.
City slid from second to fourth, nine points behind Chelsea, after Ella Toone's hat-trick for their bitter cross-town rivals dealt a serious blow to their title hopes.
Reigning champions Chelsea took an early lead through Catarina Macario, with Erin Cuthbert and Aggie Beever-Jones also scoring in the first half to send them in 3-0 up at the break.
Sandy Baltimore netted seven minutes into the second half and a late Amber Tysiak own goal completed the rout as Chelsea remained unbeaten, with 10 wins from their 11 league games this season.
Across London, Arsenal's Leah Williamson gave her side an early breakthrough before a four-goal barrage after the break saw the Gunners beat Palace.
Sunday's late kickoff turned out to be a thriller as the Red Devils, who had never won away to City in the WSL, raced out to a 3-0 lead after 36 minutes, only to concede twice before the break.
However, Toone completed her hat-trick in the first minute of the second half and United were able to hold on to take the three points from their most impressive outing of the season.
Liverpool got the second half of the season underway on Friday with a 2-1 home win over Brighton & Hove Albion, while Merseyside rivals Everton were held to a 1-1 draw at home to Aston Villa on Saturday.