Villas-Boas became the Blues' fifth manager in four years this summer, replacing Carlo Ancelotti, who was dropped just one season after securing the domestic double.
Considering the huge demands made by owner Roman Abramovich, it represents an extraordinary leap of faith from the mega-wealthy Russian.
Villas-Boas only has two seasons of top-flight experience in the Portuguese Liga behind him - his performance at Porto last season was impressive considering he won three trophies, including the Europa League, and the title by 21 points.
And at just 33, he is the same age as some of the players he has taken charge of at Stamford Bridge.
"It is a big step for Chelsea and an enormous challenge," Ferguson said.
It took the Scot back to the start of his own career almost four decades previously.
That was at East Stirling, where Ferguson was employed on a part-time basis and collected just ?40 a week - his first task being to find himself a goalkeeper because the Scottish minnows did not have one.
"I was 32 when I started but I was managing a wee Second Division team in Scotland," Ferguson said.
"All I had was a physio. I had no assistant manager or anything like that.
"He has the advantage, irrespective of his age, of having the staff he wants to have.
"It is a strong possibility he will have enough staff to overcome that type of move."
Villas-Boas has already appointed former Chelsea midfielder and West Brom boss Roberto di Matteo as his new assistant and installed Ivan Ortega as his fitness coach.
Further appointments are bound to follow as Villas-Boas adjusts to his new environment.
"He knows the club," said Ferguson.
"He has been there before so that is an advantage.
"He has a very experienced bunch of players there and for a young manager having to go to a club of that size, experienced players are a help to him.
"We expect Chelsea to be challenging again."
Source: Team Talk
Source: Team Talk