I've won 13v1 on GF before;
I've seen Axiom win 8v1 in a lb before against 82nd;
I've seen and done more before I started recording like 7v1 against 2eGren a long time ago in a NWL match and winning 4v1 against Mik, Svensson, LameHorse and another guy I forgot in a 4v4 tournament. Nowadays I don't think the skill of the players is as high as it used to be but the best players I can think of all time are players like Axiom, Evan, Akame, Xeon, LameHorse, JHS, Rikimaru and Eddie (there will be more I've missed but these guys were all amazing at their peaks).