The England international striker scored a first-half brace on Thursday to take his tally of European goals for Spurs to 20, first lobbing Tromso goalkeeper Marcus Sahlman before coolly slotting home a second in the 30th minute.
Christian Eriksen added a third late in the piece to cap an impressive performance from Tottenham, who sauntered their way through large spells of the match.
And Tottenham manager Villas-Boas was pleased with the impact Defoe was able to have on the game, despite largely playing second fiddle to close-season arrival Roberto Soldado in the Premier League this season.
Speaking to ITV, he said: "Everyone knows what he (Defoe) is capable of, his record speaks for itself.
"He is keeping himself sharp and fit and he's been excellent again tonight.
"There were two great assists from Lewis (Holtby) and (Erik) Lamela, but Defoe showed great movement as well."
There were some negatives for Tottenham though, as Danny Rose and Moussa Dembele were forced from the pitch with injuries.
Villas-Boas remained positive though, happy to start the European campaign with a win in a match they were rarely, if ever, tested in.
"It was a perfect start," he continued. "It was important for us to get three points straight away.
"I think we had some good moments, it was a difficult game because of the injuries suffered throughout the game.
"But I'm very pleased in general by the performance."
