I lost my ranked game but only lost 1 LP?

So I just played a ranked game which went terribly, everyone on my team pretty much fed and we got our asses handed to us but I'm curious as to why my mate and I only lost 1 LP? Heres a link to my profile, I went 0/15/4 as Braum and my mate went 15/12/4 as Yas http://www.lolking.net/summoner/oce/2030249#matches/134492191 TBH I don't care that I only lost 1 LP I'm just unsure as to why I lost that much and not more. If it's any help i was on 56 LP then dropped to 55 LP for anyone who thinks it's bc i was already on like 1 LP or something like that.