Defoe claimed earlier this week that he would have to consider his future if he did not play regularly, but Villas-Boas calmed fears the striker, who scored a fine strike for England on Wednesday night, could leave.
"I have spoken to Jermain and his agent about the situation. The talks were positive," Villas-Boas said.
"Obviously we are looking for one more striker because we need one.
"Jermain scored 18 goals last year. He was a key player and will continue to be. That's the expectancy I have with regards to his future.
"Competition is something that he is used to. The goal that he scored yesterday shows he can make the difference.
"He is tremendous. It was a great goal, he has great technical ability."