Chelsea came from behind to end Arsenal's 100% start to the season in a terrific London derby, at the end of an engaging Women's Super League Sunday.
Manchester United, West Ham United and Reading all scored three times to earn wins elsewhere, while winless Liverpool and Bristol City shared a 1-1 draw.
England veteran Fara Williams provided three assists as she starred in Reading's 3-2 win at home to Everton.
But Chelsea's comeback win grabbed the headlines and kept Manchester City top.
Arsenal's defeat was their first in the WSL since January - also against Chelsea - and saw them drop to third, as their unbeaten London rivals climbed to second.
Man City - who eased past Birmingham on Saturday - are the only side to maintain a 100% record after the opening four rounds of matches.
- Read more: Chelsea 2-1 Arsenal
- Liverpool 1-1 Bristol City
- Tottenham 0-3 Man Utd
- Brighton 1-3 West Ham
- Reading 3-2 Everton
Maria Thorisdottir's late strike clinched Chelsea's comeback victory and ended Arsenal's seven-game winning run in all competitions, in front of a noisy 4,149 crowd at Kingsmeadow.
The Gunners had led when Vivianne Miedema's astute pass picked out Danielle van de Donk to slot home, before Chelsea deservedly levelled after the break through Beth England.
It provided a sweet moment for Chelsea and their manager Emma Hayes, almost exactly a year to the day since their 5-0 home loss to Arsenal last term.
"We're all sick to death of hearing about our slow start to last season. That's been put to bed. We were terrific today," Hayes told BT Sport.
Arsenal boss Joe Montemurro added: "We played badly in the second half and got punished for it. We didn't put away the chances we created, so we're our own worst enemy."
A fine day for Man Utd despite late red card
Earlier on Sunday, Man Utd claimed their second straight win as they impressed in a 3-0 victory away at Tottenham Hotspur.
The result left both of the summer's promoted sides with six points from their first four league games, but United will be delighted with their performance.
Kirsty Hanson's deflected effort, Spurs defender Ashleigh Neville's own goal and Scotland striker Jane Ross' bundled late third gave Casey Stoney's team a deserved three points.
But 18-year-old striker Lauren James - who was named Player of the Match - was sent off for a second bookable offence in the final moments.
There were also three goals away from home for West Ham, who bounced back from their home defeat at the London Stadium against Spurs last time out.
The Hammers were comfortable winners as Martha Thomas' cool finish, Kenza Dali's penalty and Alisha Lehmann's stunning strike put them 3-0 up.
Brighton, who have two draws and two defeats so far, grabbed a stoppage-time consolation through Megan Connolly, but that was their only effort on target.
The Seagulls stay ninth, but the bottom four are now four points adrift of eighth-placed Spurs and the rest of the pack.
Williams grabs a treble of assists
At Adams Park, Jade Moore scored twice as Reading beat Everton in a five-goal thriller, which included four goals in the opening 23 minutes.
All of Reading's goals came from Williams assists from set-pieces, with the 35-year-old midfielder proving a constant threat.
Chloe Kelly and a Lucy Graham had seen the Toffees equalise twice early on, before Royals substitute Lisa-Marie Utland headed in a Williams corner to win it.
Reading have a game in hand on their rivals, after the postponement of their game against bottom side Birmingham because of a waterlogged pitch last time out.
Just one point above 12th-placed Birmingham are Liverpool, who remain without a win but did at least score their first league goal of the campaign on Sunday.
The Merseyside club fought back to draw at home against Bristol City, who also remain winless but are a point better off in 10th.
Ebony Salmon had given Bristol City an early lead with a speculative strike but Mel Lawley levelled from the penalty spot after Rinsola Babajide was brought down in the second half.