Chile is 18th because in the recent history (last 4 years or so) they haven't lost many games, therefore it's well deserved...or maybe not, they should be higher. Greece is 13th because the rankings take into account a lot of years (I think they date till 2002 or so), of course older years have much less importance, thus that Euro gives them less points than, say, Spain's 2008 one.
Anyway, on the match, Chile had excellent generation, but it's clear they lacked a striker. Which will be solved in the next match when Suazo is fit to play. Alexis Sánchez is simply an outstanding player