Coming off a campaign during which he scored 21 league goals, Kane's struggles mirror his team's – with Mauricio Pochettino's men ninth in the Premier League table.
The England international is still yet to find the net for his club this season, including in over 500 top-flight minutes, yet Vertonghen has backed him to turn his fortunes around.
"He has just been a bit unlucky. He scored for England and in the training sessions he has been doing very well, so the goals will come," he said.
"He's not a guy who will just have one good season and then you never see him again. He has the qualities to perform and the goals will come eventually."
A second-half goal from Son Heung-min was enough to give Spurs just their second win of the league season against Crystal Palace and Vertonghen said he is excited for the future.
"We looked very solid for 90 minutes, we played well at the start of the season but we weren't that focused at the end of the games," the defender said ahead of Wednesday's League Cup clash against Arsenal.
"But things are looking very good. We have great young players and a good mix, so there are great things for the team if we can keep working like this.
"It looks very good for the future."