Spurs sit in fifth place in the Premier League, ahead of United in eighth, but with only three points separating the top five, Villas-Boas believes the title race remains wide open.
Tottenham's derby rivals Arsenal sit at the Premier League summit but the Portuguese manager believes the fixture list has been kind to the Gunners, who have yet to face any of their fellow top-four finishers from last season.
Ahead of the league visit of Hull City to White Hart Lane on Sunday, Villas-Boas said: "The Premier League looks extremely open this season.
"It's so open that the 14th team has 10 points. Everyone is so tight together.
"I don't think it has that kind of impact, we will see the big fixtures coming for Arsenal, they have only played us and they will play other big teams.
"So I would suppose the fixture list at the moment is in favour of Man United because they have played all of the big teams so far.
"That will give them a chance to bounce back for sure."