As Charli I was searching for my phone when I noticed her positioning herself for maybe six seconds before the entire sold-out crowd noticed her presence and erupted in a massive roar. In all the shows I’ve seen, in all the arenas across the country, this might have been the loudest crowd explosion I’ve ever heard. In professional wrestling, it’s called a “pop” – when the audience thinks whatever is happening in the evening’s scripted entertainment is so extremely good that it deserves an above-average ovation, something that goes beyond normal cheering. Who doesn’t want to see these two give their best at the live show?

And also: Does Brat wrestle? I thought about this as I watched Charli and Troye Sivan’s collaborative Sweat tour reach its peak with Lorde’s cameo appearance in New York. It had been a few years since Lorde appeared on stage in New York – although she was spotted at Clairo’s New York show last week, leading Vegas, or at least the pop stars, to think there was a good chance she would join Charli at MSG . This is such good writingI thought as I watched Lorde perform her amazingly good verse on the “Girl, so confusing” remix. That’s what I meant both in her actual words and in the narrative of the evening. Here was Charli XCX, a stiletto at the top of the zeitgeist, commanding the audience so completely that she could have played brat on Spotify with advertising and everyone would have said: Yes, thanks. And yet here she was bringing out her New Zealand boyfriend to sing a duet about their entangled jealousy, insecurities, sisterhood and fame. It was so real. It was so wrong. It was so brat.

Before that triumph, new pop class leader Addison Rae came out to sing a tongue-in-cheek simulacrum of pop music, “Diet Pepsi” featuring Charli and Troye and their remix of “Von Dutch.” It was good, and the crowd was still thronging her entrance, but I almost feel bad for Rae, whose looks were dwarfed by the mere image and memory of Lorde and Charli strutting arm in arm up the runway , while Lorde spat, “You leave like a bitch.” In fact, I think the entire show after “Lorde” felt like a collective processing of the incident. In the row below me, people were texting, posting, and staring at each other in disbelief as they witnessed Lorde and Charli on stage together. I think I’m still in disbelief too.