He was all charisma; making eye contact, waving, blowing kisses, mouthing "I love you"s, winking and flirting with the audience and somehow, he morphed his pop concert into a rock gig.
That's no exaggeration. Remember those mosh pits that left you bruised and soaking wet from other people's sweat, watching people being dragged out of the front lines by security? This - I kid you not - was no different.
Styles lapped it up, prompting the crowd to give more applause and throwing his head back to bathe in it which, in a world where pop stars are forever trying to be humble and down-to-earth, the pure rockstar arrogance was actually just really fun to watch.
His ballads evoked tears, seas of phone flashlights and swaying arms and the repurposed One Direction hits (Stockholm Syndrome and What Makes You Beautiful) made fans go crazy, but the real highlight came from the eagerly anticipated hit, Kiwi.
Styles started the track singing barely a couple of lines before letting the crowd take over completely. Then he stopped, started again and stopped again.
"Ok, let's have a little discussion," he said, getting the crew to turn on the house lights. "I find myself in a predicament...here I am, about to sit my song Kiwi with a room full of Kiwis and I have to be honest with you...you weren't loud enough, ok?
"My ego is very large and I cannot take it if you're not gonna go for me with this one. I will stand here and do this is many times as it takes to get it right. Are you ready?"
And then he launched back into the track, screaming into the mic, dancing like a madman, spraying the audience with water and spitting into the air and it was electric.
After an encore of ballads (From the Dining Table, Fleetwood Mac's The Chain and hit single Sign of the Times), Styles thanked the crowd for their support and said: "please know, every single one of you in this room, I love you so much".
And as he waved his final goodbyes and blew his final kisses, everyone around me seemed to burst into tears.
That was when it hit me: Harry Styles might just be the younger generation's Bowie or Jagger.
Not in the sense that he's achieved what they did - not by any means - but between the style, performance power, charisma, talent and pure hysteria...he could just become that same kind of rock star for a new generation.
