Spurs failed to win in their first three games under the 34-year-old, but have turned it around with three consecutive wins in recent weeks.
The Portuguese told The Express: "I have never doubted my abilities, I always trusted them. It's funny how things change so dramatically.
"The Premier League is completely unpredictable. We started the season [badly]. We are now fifth from the top. You have to perform at this level. This is the early stages in the Premier League."
Villas-Boas took charge at White Hart Lane over the summer, after the club sacked Harry Redknapp
Tottenham host Aston Villa tomorrow.