West Ham have failed to win since the opening day of the season, while Spurs have only lost one of their opening six fixtures, but Villas-Boas is still expecting a tough game from their London rivals.
"They are still a very objective and aggressive team. They are very direct and we know what to expect against them," Sky Sports News quotes him as saying.
"We will have to be alert at set plays, crosses into the box and make the play very, very strong.
"We were successful against them last season, winning home and away, and we are highly motivated for the game against West Ham. A London derby is always difficult, so it will be an extremely difficult match."
Tottenham are currently fourth in the Premier League table with 13 points from six matches.