Defoe has now scored six goals this season, underlining his value to the Tottenham squad in what has been an outstanding opening to the campaign.
They do face Chelsea at the weekend though, so Villas-Boas is not getting carried away.
"It changes very quickly," he said. "That is the nature of the Premier League and the excitement that it brings.
"At the moment it is going well for us. That always gives you confidence and motivation for the games that are coming.
"Chelsea is a different proposition. It is a very difficult game."