Spurs have already beaten United this season, when they won for the first time at Old Trafford since 1989 in the opening weeks of the campaign.
Villas-Boas reckons Tottenham have improved since that 3-2 victory now that he and the squad are more settled.
"We have got to know each other better," Villas-Boas said. "Obviously we had a new manager in place and lots of changes to the playing squad too.
"I think we've got a consistency - at that stage at the end of September we would have welcomed the most amount of matches as possible so as to get to know each other a little bit better.
"I think both teams have improved but United compete for titles, have great players in their squad and they come here fully motivated I think, so it's going to be a hard game for us.
"What we've changed from the time we played United is that we have improved our form at home. That is something United will recognise. White Hart Lane is never an easy place to come to.
"We're also on a great run of results and we will create big difficulties to United if we approach the game in the right manner."