Reigning Women's Super League champions Chelsea moved to the top of the table with a 2-1 win against challengers Manchester United.
United had led the way at the start of play but suffered a first defeat of the campaign as goals from Pernille Harder and Fran Kirby earned the Blues victory.
Harder put Chelsea in front on the half-hour mark from close range before United equalised in the 61st minute when Lauren James played a one-two with Ella Ann Toone and then curled a delighted effort into the net from the edge of the box.
Kirby hit the winner four minutes later, getting on the end of a long, looping clearance from goalkeeper Ann-Katrin Berger to calmly slot home.
Lauren Hemp scored a brace and set up another two as Manchester City beat Aston Villa 7-0 for a fifth successive win.
Further goals from Jill Scott, Georgia Stanway, Ellen White, Chloe Kelly and an own goal from Natalie Haigh added to Hemp's first-half double.
Izzy Christiansen bagged a pair of goals as Everton recorded their first win in six games with a 4-0 victory over bottom club Bristol City.
The Blues made the perfect start to their first game of 2021 as Nicoline Sorensen's low cross was turned into the net by Christiansen just four minutes into the game.
The visitors, yet to taste victory this season, held firm until the 38th minute when Benedicte Haland fumbled a cross from the left and Simone Magill was left with a simple tap-in to double the advantage.
Christiansen effectively put the game to bed in the 57th minute when she got on the end of a cross from Lucy Graham and a Megan Finnigan header wrapped it up for the Toffees six minutes later.
Third-placed Arsenal had to settle for a 1-1 draw against Reading.
The Royals went ahead within five minutes when former Gunner Emma Mitchell whipped a free-kick into the box and Lauren Bruton turned home.
The Gunners clawed themselves back into the game against the run of play on 39 minutes, however. Jill Roord's header was well saved by Grace Maloney, but she could only parry the ball into Vivianne Miedema's path and the WSL leading scorer tapped home from two yards.
Lucy Quinn's first-half goal earned Tottenham a 1-0 victory as Olli Harder made a losing start to life as West Ham boss.
Brighton's winless run was extended to four games as they played out a 0-0 draw with Birmingham.