Spurs blew a 2-0 lead established by Brennan Johnson and James Maddison to lose 3-2 at Falmer stadium as Brighton fought back by goals from Yankuba Minteh, Georginio Rutter and Danny Welbeck.
Hurzeler said, "The first half it was not a tactical thing that we conceded the two goals.
"It was playing with intense, fulfilling the match-plan with energy - that was the main topic. That is what I had to get back at half-time. It is the job from the players they played an amazing second half and did enough to win.
"I think little bit (of confidence) was missing. Being ruthless is the most important, in the duels we were not ruthless and if you win the personal duels and get the ball into the opponents half you get self confidence - that was the biggest change.
"Tottenham had some moments, but most of the time we controlled transitions.
"I always say 'we have enough quality to always score'. It is always important to learn from the first half."
On his attacking players, he said: "In every team it is important to have individual quality - the four players in front they shouldn't define themselves on individual quality. They should define themselves on how they work for the team.
"I am happy for them - they worked hard and they deserved it."
On Welbeck, Hurzeler added: "He is very free. He seems to be young, he is in great shape and he has taken care of himself.
"He is a role model for young players. It is impressive to play in the Premier League with a big age.
"I enjoy working with him, he's a big professional and a lot of young players should see how hard he works and see what is possible in the football career."