Well therein lies the answer, Citeh weren't brave in attacking and you have to be from the outset (changing to 3-4-3 midway through a game is just insanity).
No doubt there are very obvious flaws to going that way regards to full-backs, they're full-backs because they are weaker attackers than forwards but that's the modern game, it's why possession is so key for a lot of the game; though obviously that does not mean that you can't make the most of counter-attacking opportunities when they present themselves.