I think SSB got overconfident after the first teamfight in mid lane (which was probably the best teamfight by them in the game, consider how weak Kass and Twitch were relatively at that point) where they broke through LMQ's ultimates and blew up their backline (Maokai/Rengar commit forcing Shockwave and Equalizer, then Kass with Janna, then Twitch). Or at least Deft thought they'd won since he'd been running around blowing people up at will for a few minutes afterward.
LMQ missed their chance though. SSB grouped for an early dragon and ackerman, on the strongest early teamfighter in the game... used his Equalizer on absolutely nothing. The game was lost there - you can't let Kass get to late game with a composition based around two big ults (three including the Tidal Wave), or he'll just jump around you, force you to waste your cooldowns, and let Mao/Rengar/Twitch do the work. The last two teamfights were one-sided stomps because Kass got too big, and SSB getting an early dragon that they had no right to was a big help in getting him there.
