With so many new arrivals at White Hart Lane this summer, the 24-year-old attacking midfielder has been somewhat overlooked.
But, returning to the starting line-up in Saturday's Premier League clash at home to Norwich, after an injury in training to Nacer Chadli, Sigurdsson responded with both goals in a 2-0 victory that lifted Spurs up to second in the early table.
Villas-Boas said: "Sigurdsson is a big fighter in this squad, always hoping for his opportunity to arrive.
"When it does arrive, he puts on performances like this. It was the same for him last season, in February and March. We saw his best level today."
Sigurdsson's first goal was set up by debutant Christian Eriksen, who quickly endeared himself to the home crowd with a stylish performance.
"He already has so much experience from Ajax," said Villas-Boas of the 21-year-old Denmark international.
"He really linked the game well for us in the final third today. It's easy for him to find his passes when his quality is so good."
Reflecting on the overall display, in which Spurs enjoyed 69% possession overall, Villas-Boas said: "It was an excellent performance. I really wanted us to put it to bed.
"The second goal early in the second half gave us immense tranquility. I think we played really well, and created great moments of football.
"I think we probably deserved a couple more goals. After an international break, it's always difficult to get the players back but they responded ever so well.
"Norwich is a team that we couldn't win against last year, and this gives us good satisfaction because they are a very difficult team to beat."