The Brawn worked beautifully around the tight and twisty streets, narrowly pipping Ferrari’s Kimi Raikkonen who posted second.
Button’s teammate Rubens Barrichello got third, with Red Bull’s Vettel in fourth.
Red Bull weren’t particularly happy with their quali performance, especially as Vettel was running really light on fuel – they chucked everything at it but it just didn’t come together.
And in fact, Jenson’s heavier than everyone behind him, other than Rubens, all the way back to Fernando Alonso in ninth.
Mark Webber told me that his eighth spot should be good enough for at least sixth tomorrow, and that he was going to take it easy with a morning sea swim before the race.
He reckons that the Brawns are much more suited to this circuit than his own car, as the RB5 is more happy with longer straights.
He doesn’t think that the Monaco jelly fish are that scary either, compared to the ones he’s used to from back home in Australia.
Lewis Hamilton had a shocker of an early bath after looking really promising in practice, knocking himself out in Q1, with a very long, lonely walk back to the pits.
What’s your predictions for the race? And check out the full times on BBC Sport’s site.