Fnatic lost 9-16 to ViCi, too on Overpass, dude, who knows. A good CT side could be the difference for the French guys.
FURIA, I believe they have a chance (not great, obviously) cuz I think they have a good chance to win their map pick (Train or Nuke). And in a third map, everything can happen. c9 would play more nervous than FURIA in a decider map, in my opinion cuz FURIA "has nothing to lose" and c9 has a LOT to lose with a 1-3 in this Challengers Stage.