Women's football in England is enjoying a break-out season in just about every metric imaginable.
Games in bigger stadia attended by record crowds. New platforms showing the action. Vastly increased media coverage (long overdue).
Everyone involved with the FA Women's Super League (FAWSL) saw the opportunity provided by the success of England's Lionesses in the FIFA World Cup this summer - and has made the most of it. 2019 will be remembered as the year that women's football truly hit the mainstream.
What the sport will now find is that, as with any sector, hitting the mainstream brings with it as many challenges as opportunities.
One such area of opportunity and challenge is the extent to which women's football absorbs the culture of the men's version of the sport in the way that it brands itself.
Specifically, how does women's football harness the rivalries from men's football, whilst avoiding the toxicity that men's football endures? In most sports, passion does not equal hatred. In men's football, too often it does. How will women's football avoid this?
This weekend in the FAWSL, Spurs played Arsenal in the new Tottenham Hotspur Stadium and Liverpool hosted Everton at Anfield.
The game at Tottenham, in particular, made history.
Spurs were promoted to the FAWSL this season along with Man Utd. Neither club is historically a giant of women's football but their names (and rivalries) carry enough weight from the men's game to have had an immediate effect.
Man City's game versus United in September was played at the Etihad and broke the FAWSL attendance record (31,213). A record which lasted until this weekend when 38,262 watched Spurs v Arsenal.
It was the first time an Arsenal team - men or women - has played at the new Spurs stadium and therefore many Arsenal fans took the opportunity to attend. By all accounts home and away fans mixed freely and without incident in a way that would be unimaginable at a men's fixture.
On the same day, 23,500 watched the Merseyside derby. Before this season, the FAWSL's record attendance was 5265. This is an unprecedented moment.
Since there was no history between Arsenal and Spurs in women's football before this game (a point made in a very good article on the popular Arsenal website Arseblog) it's clear that importing rivalries from men's football is good for raising interest and converting that to ticket sales.
Very happily, this didn't cross over into the tribal hostility which is so common in men's football (although it's worth saying, Arsenal-Spurs, even in men's football, tends to be less toxic than other London rivalries).
The balance achieved around this fixture is central to the key point: are these rivalries somehow transplanted from the men's version of the game, or simply associated with those clubs, regardless of gender, and how should the rivalries be used positively?
It was certainly interesting to note the tone of voice from Arsenal, as well as the club's kit partner Adidas, after Sunday's result ...
In contrast, Everton's tone following their victory over Liverpool was a bit less adversarial.
Either way, it does feel like we are creating new women's football rivalries, which can only be a good thing for ticket sales, future broadcast deals, merchandise and more.
Up to a point.
Rivalries are good, but in men's football, the toxicity that comes with them is not.
How does women's football build the rivalries without sleepwalking into the problems experienced by the men's game? How will we spot when that line is zooming into view, and work together to ensure the women's game doesn't cross it?
Kieran Theivam, who has reported on women's football in the UK for longer than most, wrote in The Athletic in September about chants that were heard in the Man Utd v Liverpool game.
Nobody involved in football, either the men's game or the women's, wants to hear those chants at games. Therefore we all have a responsibility - clubs, sponsors, marketers, all of us whose roles touch the sport - to create rivalries which do not tip past that point. Tension - yes; toxicity - no.
To successfully balance those two sides of the same coin, women's football must use the incredibly strong foundation which so many people have worked hard to create, to decide what it wants to be.
Does Spurs v Arsenal mean the same thing, whether it's men's or women's football, or will it come to mean slightly different things? Is any fixture between Man Utd and Liverpool territorial and confrontational, no matter who is wearing the shirts? Or should the tone of voice be different, even held to a higher standard?
For those of us involved on the digital side of sport, is there a danger that adversarial marketing raises the risk of women's football sleepwalking into the same problems men's football is blighted by still? Does marketing stoke the toxicity in men's football, or merely reflect a sanitised version of it?
For women's football or any other sport, resolving these sprawling, complex questions requires a plan.
At Seven League we work with clients to decide their business needs, audience needs, and identity. In women's football, this weekend showed the clear business need (keep growing the game on its current, exponential trajectory) and also the audience need (more people than ever are passionate about women's football and will want more from it: more games, more broadcast, more content ...)
The fascinating next question is: what will that identity, and tone of voice, be?
Culture, and learned behaviour, are some of the hardest things to change once they're set in, across any sector.
At this point, women's football is experiencing a boom which is a credit to all those who have worked so hard to get here, and crucially it's achieved this whilst maintaining a culture that is strong, positive and healthy.
The responsibility for continuing to build this in the right way, even as the sport continues to attract record-breaking, mainstream football audiences, lies with us all.