The 31-year-old's deflected effort wrapped up a workmanlike 2-0 win at Sheriff Tiraspol, putting Spurs on the brink of qualification to the Europa League round of 32.
"It is some achievement," Villas-Boas said. "If we continue like this, there is a big chance he will break the record.
"It will be another great achievement for him. I am sure he will achieve it.
"Let's not celebrate it before it happens, but it will be a great record for him and the club. It was another great performance by Jermain."
Jan Vertonghen's header gave Spurs the lead after 12 minutes, but the hosts had a goal disallowed and were a persistent threat until Defoe struck for the sixth time in this season's competition to kill them off.
"They had some great opportunities on the counter-attack," Villas-Boas added.
"The game could have easily gone to 1-1 as after we scored they had so many chances to level the score.
"They looked good on the counter-attack, had some great moments and we have to recognise that.
"A draw would have been a fair result, but the second goal is always important in games like so this, so both teams were creating.
"We were fortunate to get the second goal to kill the game, but it could have gone the other way."
The victory leaves Spurs top of Group K with maximum points and with five clean sheets from as many games.
They could have secured their qualication on Thursday night, but Anzhi's 1-0 defeat of Tromso means they will have to wait for Sheriff's visit to White Hart Lane on 7 November.
"In general, we did enough to win the game and get to nine points, which was the objective so we can achieve qualification at the next game," added Villas-Boas.