Andy Carroll has been missing this season with a heel injury and in his absence Sam Allardyce's side have scored just four goals in six Premier League matches to leave them hovering above the relegation zone.
But Villas-Boas is refusing to take the threat they pose lightly, despite the fact they head to White Hart Lane without a victory in eight away league games, having failing to score in their last four.
"They are still a very objective and aggressive team. They are very direct and we know what to expect against them," he said.
"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."
Villas-Boas was boosted ahead of the game by the news that club skipper Michael Dawson has signed a new three-year contract and he is hoping striker Emmanuel Adebayor will also commit his future to the club.
Spurs were keen to offload the Togo striker during the summer transfer window but the player refused to leave and although he is currently ruled out through injury, he has been battling summer signing Roberto Soldado and Jermain Defoe for a place in the side.
"I think his motivation will be high," Villas-Boas said of Adebayor.
"At the moment we have found extreme comfort in playing one striker rather than two like last season.
"What Ade will give us is that possibility, that link-up play he does so well with somebody else.
"At the moment we continue to play with one striker. We scored so many goals and we don't suffer, so it looks like the way forward for us.
"All three of them will be in competition for that place."