The humiliating 6-0 defeat at Manchester City last weekend saw the knives come out for manager Andre Villas-Boas, but the Belgium defender sees no reason to panic.
They take on in-form Manchester United on Sunday and Vertonghen hopes a positive result can start them on a similar run to this time last season when they went 16 games unbeaten.
"You cannot write us off," Vertonghen said. "We did not do well in this period last year with losses against Wigan and City and Arsenal.
"But we then had incredible months in December and January and I think that is what we are aiming for now.
"We want to do well in those two months and then I think we can be back easily because the top half of the table is so strong and everybody can win."
Vertonghen feels the 2-0 win over Tromso in the Europa League on Thursday helped restore their confidence a little.
"It was important for the group to come away with a win in difficult circumstances," he added.
"We are so motivated to do well on Sunday especially after the City game. I am confident for that game because the supporters will be behind us and we are motivated to do well after such a loss."
He knows the tough challenge ahead for Spurs' defenders, though, with the fearsome Wayne Rooney-Robin van Persie strike force heading for north London.
Vertonghen added: "Rooney and van Persie are quite similar to the City strikers. They move well and play better and better together now.
"They are at least the same level as Negredo and Aguero. They are unbelievable.
"They are the most important players but the strength of Manchester United is that they have always been stronger as a team together."