Manchester City bounced back from successive defeats to beat rivals Manchester United at Old Trafford and put their Women's Super League title challenge back on track.
In front of a record 43,615 crowd for a Manchester United WSL game, Gareth Taylor's side reminded the city of their superiority in the women's game, coming from behind to seal victory despite having only 10 players for the final 15 minutes.
United captain Katie Zelem had put the hosts in front, scoring from the penalty spot after England defender Alex Greenwood blocked Melvine Malard's shot with her arm.
However, City's Jill Roord and team-mate Lauren Hemp scored within two minutes of each other to turn the game around in the visitors' favour, and they added a third after the break when Khadjia Shaw charged down goalkeeper Mary Earps' clearance.
With City seemingly in control, United were given a lifeline when Laia Aleixandri was sent off for a second booking, but Marc Skinner's side could not find a response.
Victory moves City up to third in the WSL table, six points behind leaders Chelsea, while United sit one point behind in fourth.
Kelly revels in victory as City boost title hopes
Following back-to-back defeats by Arsenal and Brighton, City boss Taylor said this week his side needed to go unbeaten for the rest of the season to be in with a shout of winning the title.
They came to Old Trafford under pressure to win and started with intensity, pressing high up the pitch and forcing goalkeeper Earps into some wayward clearances.
Greenwood, Shaw and Alanna Kennedy all had chances from set-pieces, while Hemp tested Earps before United had been able to settle.
Eventually, the home fans had something to cheer about when summer signing Malard began to show creativity, first spinning away from Leila Ouahabi, then flicking the ball over the same opponent to slide it through to Ella Toone, but the England midfielder scuffed her shot in the box.
Malard was United's brightest spark and was rewarded when Greenwood, returning to the City side following a spell out with concussion, could only block her shot with her arm to give away the penalty.
That seemed to spark life into the hosts, cheered on by thousands in the Old Trafford stands, and they thought they had doubled their lead when Geyse pounced on a rebound from her shot to slot the ball over the line.
However, a tight call from the officials went in City's favour as it was ruled out with the ball having gone out of play before Geyse squeezed it in.
Three minutes later Roord fired in the equaliser after Chloe Kelly had beaten Lisa Naalsund on the left, and Hemp punished United again moments later.
Boos rang around Old Trafford as Kelly celebrated in front of the United fans, cupping her ear after Roord's equaliser, before slapping the City badge on her chest when Hemp made it 2-1.
She was one of many players revelling in the victory at the full-time whistle, as City's players raced over to their supporters in the corner dancing and fist-pumping, while United's team huddled around Skinner looking hugely disappointed.
"It's becoming a proper rivalry rather than it being 'oh, it's a great day to come to' and that's credit to the fans," said United boss Skinner.
"They want to see the performances. The players have to feed into that. If Chloe [Kelly] has celebrated like that, then that's part and parcel of a derby.
"I like the rivalry. We were on the losing end to it tonight so it hurts but we have to be galvanised by the fact that we want to be on the other side of it after the next game."
Both teams' priority will be a top-three finish to seal qualification for next season's Champions League, and City know this is a big boost to their WSL title hopes - they could not afford to lose further ground on leaders Chelsea.
United miss chance to make progress
Having watched City compete for trophies for the past decade, United are finally in regular conversation with the WSL giants and this was an opportunity to show their progress on the big stage.
It was always going to be a challenge - City have lost just one of their seven WSL games against United, though that came in the most recent derby in May.
United strengthened in the summer transfer window to build a squad capable of playing in Europe, but defeat by Paris St-Germain in the Champions League qualifying rounds ended their hopes early.
It means all focus is on the WSL title but this is a damaging defeat, to add to disappointing draws with Leicester City, Brighton and Arsenal, which has opened up a gap between United and Chelsea.
City looked comfortable throughout, even when down to 10 players, and for all United's summer spending, they failed to find a response with the backing of an expectant Old Trafford crowd.
There were too many individuals errors, including Earps' hesitance when closed down by Shaw following a poor backpass from Maya le Tissier to make it 3-1 to City.