The critics have already pointed to his age as a cause for concern but Villas-Boas will attempt to prove them wrong by satisfying Roman Abramovich's thirst for trophies.
Chelsea's new manager said: "This job is all I ever wanted.
"I accept people may view it as a gamble employing someone so young, but if I didn't believe I could succeed what is the point?
"I have expectations and want to look back on a career I can be proud of. I want success."