Defoe netted for the seventh time in four starts this season to help Spurs win their Europa League clash in Russia and move him to within a goal of Martin Chivers' club record European haul.
He is also fifth in the club's all-time scoring list but it is big-money summer signing Soldado who has been preferred as the lone striker in the Premier League this season.
Villas-Boas was impressed by Defoe's performance against Anzhi and full of praise for his attitude, admitting the England man had given him a lot to think about after taking another opportunity.
However, squad rotation makes it likely that Soldado will come back into the side on Sunday, with Villas-Boas saying: "We have to judge recovery and the fact that JD was involved today and Soldado wasn't. Everything will come into consideration.
"We have been extremely happy with the performances of both. It is a question of deciding what is best for the team.
"It was another great goal, a great finish. It's really good to see him out there again doing extremely well whenever he's given the opportunity.
"He is a great professional, has a great attitude and now he's only one off Martin Chivers so it's a real great achievement for him.
"I think he has the ambition this season to go even further up the ladder in this record tally behind Martin Chivers and as an all-time goalscorer so I think that plays highly in his motivation, definitely."
Defoe broke the deadlock in the 34th minute before Nacer Chadli added a second, and Spurs comfortably withstood a spirited response from Anzhi after half-time to take control of Group K with maximum points from their opening two games.
"It was a very good first half, where we were in control," Villas-Boas said.
"It is always tricky because Anzhi looked to be very threatening on the counter-attack, so attacking our spaces whenever we lost the ball.
"But I think through what we did in the first half we deserved the result.
"We lost a little bit of control in the second half, kept giving the ball away and they had the upper hand, but even so we were defensively sound."
The only negative on the night was a knock sustained by Younes Kaboul, forcing him off 20 minutes from time at the Saturn Stadium.
The Frenchman has been plagued with injuries for the best part of 18 months and suffered another setback in Russia.
"It's a bit of a problem because of his injury in the knee it has taken him time for his body to adapt to new positions on his run," Villas-Boas said.
"Because of that he's putting extra strain on his muscles and keeps getting small contractions that limit him finishing the games.
"At the moment it doesn't look very serious but it will force him to stop for a week or so.
"When we get him back we will give him a one-week or two-week preparation to be physically better."