A quick morning puzzle

A couple of months ago, I had a rare occasion to play against a fellow Australian in the 4NCL league match weekend in England. The Aussie in question is IM Justin Tan, an extremely talented young player who probably hasn't received the attention he deserves for two reasons: (1) He shares exactly the same name as one of Australia's former chess prodigies (leading to all sorts of database confusion!), and (2) He comes from an astoundingly vibrant generation of chess talents in my country, including the phenomenal 14-year-old IM Anton Smirnov and former World Under 12 Champion IM Bobby Cheng.  

For these reasons, and having recently moved to England for a stint, poor Justin is relatively unknown in the Australian chess community. However, I've respected his talent ever since he very nearly blew me off the board way back in 2011. Justin's chess results have shown a remarkable climb in the last few years and he recently gained the IM title, which led to a nice write-up in the British press. This perhaps inspired him to take a gap year to focus exclusively on chess, and so now we wait to see just how far his talents can go. I suspect we will be surprised!

But enough chat; I did after all promise a 'quick' puzzle. In our encounter, I once again managed to slime my way to a second victory in a long queen endgame, but also once again it was somewhat undeserved. After almost seven hours and two cancelled dinner reservations, we reached the position after my confidently-played 83...Kf1. Justin played 84.g4 and resigned a move later, and that was all she wrote, as we say. Or was it? 

I'll post the solution tomorrow!

SOLUTION:

My 83rd move was a huge blunder; Black could still win by sending his king to the other side of the board. As correctly pointed out in the comments, the very cute draw begins with 84.Qb1+!!. The key point is that if Black promotes to a queen, White either forces a draw by perpetual check, or checkmates the black king!

That's not entirely the end of the story, though. Black can still play for a win with 84...e1=N!. The ending QNvQ is a book draw, but Black has one final trick up his sleeve. Check out the variations to see more.