Goals from Bojan Krkic and Jonathan Walters gave Sunday's visitors to White Hart Lane a 2-1 Premier League victory that their performance merited.
Nacer Chadli's sensational second-half volley gave Tottenham hope, but Stoke were able to hold on following the late dismissal of Kyle Naughton.
A frustrated Pochettino lamented an early miss from Harry Kane prior to Bojan's fifth-minute opener.
"I am unhappy and disappointed with the performance and the result," he said.
"We need to find a solution, we started the game well, and created a good chance with Harry Kane, but after we conceded the first goal we started to play uncomfortably.
"We made rash decisions and that is not possible in the Premier League.
"In the second half we tried to fix some things to manage possession of the ball, but at 2-0 down it is difficult to change the game.
"There is no added pressure. We need to find a solution, this is my job, this is my plan in the next few weeks, we need to find a new mentality."
Defeat drops Tottenham into the bottom half of the table and increases the pressure on Pochettino, who succeeded Tim Sherwood in the close season.
