Last round, Pikachu snuck through because Vivi and Tidus screwed each other over. In the match prior to this, Luigi and Ganondorf hurt each other a lot and it allowed Master Chief to roll into first place. A lot of other matches worked in much the same way as well. And not a single one of those matches prepared people for Pikachu doing this. Even with the adored Yellow sprite and being against three other Capcom characters, almost no one expected Pikachu to advance in this match at all, let alone score first place and just thoroughly screw over Leon Kennedy like this.