Remember the time during Air Poker where Baku tells a story about a man who plants things in various place like a card in the river in hope that one day he can use it in a gamble? That's what he's basically done when he selected the "Time" card during the "Ban" game.
He knows that there will be a leap second on Jan 1 2006 at 9:00am (way way back then) where the clock will go 8:59:60 and then 9:00:00 (Notice that the clock went 'DONG' twice, the leader turned at the first one). There's a lot of foreshadowing happened (like in his dream sequence where he walked on the 60 tile instead of 0), but I guess it's really hard for people to theorize this winning condition (though I've seen quite a few in the comments coming close).
How he manage the time though to make him 'D' during the leap second is what he's been doing the entire match, adjusting when to 'die' and when to delay the match in response to how HAL plays (note the time when he just sat at the chair so he can manipulate the referee to tell the time)