In an all-too-brief one-hour set, she delivered an intimate but exciting gig that some die-hard Vickers fans have already claimed was her best ever.
This was my first look at Diana Vickers as a live performer (not counting live performances on TV, obviously) and it was a far cry from the innocent-little-girl act she played back on The X Factor.
Present-day Diana is all grown up, and her music is maturing too - but there's still plenty of fun in there, too.
Nothing highlighted this more than Diana's own energy levels, dancing across the stage throughout each song, shedding tinsel as she went, and generally making it very difficult to get a decent photo of her...
The mandatory supply of water was there on stage, but accompanied by a large glass of red wine, another reminder that Vickers plays by her own rules.
And if anybody had missed her impressive achievement of dancing in skyscraper heels, Diana wasn't going to let them get away with it, as she pulled off a foot-to-the-head move to show off her new footwear to the crowd.
In keeping with Diana's guise as a dancefloor performer, rather than a pop act, there was a decidedly electronic feel to the night.
Support came from DJ Pasta Paul, rather than from a live singer, and that meant an hour or two of broad music tastes leading up to Diana's appearance on stage - Ashes to Ashes seemed an unusual choice with about five minutes to go until showtime, but was welcomed none the less for it.
Diana's own set was similarly eclectic, combining tracks from her new album with old favourites (including a crowd-pleasing rendition of Once, which Diana said she still loves to sing), a cover of Carly Ray Jepsen's Call Me Maybe, and lengthy dialogues with the crowd.
Case in point:
"Diana! Diana! It's my birthday!"
"Birthday boy, eh? Well I'm wearing tinsel for you, baby."
Because hey, when you're dressed like a Christmas tree in July, who cares whether birthdays and Christmas are the same thing?
In a genuinely crowd-pleasing night, there are few downsides to pick out, but just a couple of things deserve mentioning.
Firstly, while DJ Pasta Paul did a decent job of warming up the crowd, there wasn't really anything special about his performance that we could see - the music was basically the same as you'd hear on a normal night at The Deaf Institute or any similar pub or bar.
Diana's set could have been just a little longer - not much, or she'd have run out of original songs to sing, but there was no real sense of her bringing the tempo down at any point, which is a shame given the quality of some of her ballads in the past.
And the final criticism is levelled at the audience, who seemed to assume there would be an encore regardless of what they did - and not only failed to shout for more, but barely even clapped.
That made for a too-sudden ending to the night, before burly bouncers ushered everybody out and down the stairs, a stark contrast to the genuine sense of intimacy and appreciation Diana had shown to her audience throughout her set.
Overall however, I think everybody there had a good time - particularly the overabundance of middle-aged men among the crowd.
For me, the moment I really realised how far Diana has come was when the timing was a little off at the start of one track, and she recovered it as early as the second line - regardless of reputation and appearance, she is a fine and talented singer, with a lengthy career no doubt still to come.