Andre Villas-Boas' side suffered a 4-2 derby defeat to capital rivals Chelsea on Saturday, bringing a run of four straight wins to an abrupt halt. Spurs rather stumbled out of the blocks at White Hart Lane, with the hosts fortunate to be only one goal down at the interval. They improved after the break, but Vertonghen concedes that there have now been too many occasions on which Tottenham have allowed their standards to slip.
"At home we seem to play better in the second half than the first," he said.
"We need to think about how to put two strong halves together. We need to work out how to put a bit more pressure on teams from the start.
"They (Chelsea) were the best team I faced this year, but I knew they would be. I knew their players before I came here and what they are capable of.
"Chelsea are a good team but I feel we should have done better."
While Vertonghen, a summer signing from Ajax, admits Spurs have areas they need to work on, he believes they are well-stocked at centre-half, with the Belgian quick to pay tribute to the efforts of veteran Frenchman William Gallas - who has been an ever-present in the league so far this season.
"William is very experienced and with his experience he can be a very good player for us," said Vertonghen.
"He is our captain and an important player.
"He treats me like I am his little brother, so that's why he is a very good captain.
"He always wants the best for me, even though we are both centre-backs. I really appreciate him."