The 23-year-old, who was missing from their games against Chelsea and Maribor due to the birth of his first child, returned to Villas-Boas’ line-up and netted a header in 15th minute against his former club.
Clint Dempsey extended Spurs’ lead just before half-time, and although Southampton halved the deficit through Jay Rodriguez in the 66th minute, Tottenham clung on to claim three points.
“I’m extremely happy for him [to score],” said Villas-Boas. “He’s a massive player for the team.
“He’s a player who even with small opportunities can make a difference. He certainly did it [against Southampton], he anticipated the defender very well. It was good for him to get back on the score sheet too.
“He’s somebody we rate really, really highly and he can go all the way and become one of the very best.”
Tottenham’s win leaves the north London side in fourth place, five points behind Premier League leaders Chelsea, and Villas-Boas said it was vital his side picked up maximum points ahead of ties against Manchester City and Arsenal.
“I’m obviously happy with what we did in the game,” Villas-Boas said.
“We had an extremely good first half. We kept the ball well and managed to create lots of opportunities.
“We looked always in control of the game.”
He added: “We want to make the most of this run of fixtures which we have against Southampton and Wigan before we got to Arsenal and Manchester City.”
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news