Tottenham manager Mauricio Pochettino has questioned the mentality of his players after they suffered a third home defeat of the season to Newcastle.
After safeguarding a 1-0 lead at half-time, Spurs capitulated to concede two quick goals early in the second half and lacked the fight to get back in the game.
"It is not something where you can analyse the action, sort the tactical situation and move the players," Pochettino said.
"It is not easy. With mentality, we need to work hard and be stronger – like a team. This is our challenge.
"We need to speak and to create a different situation on the training ground. We know how but always you need to spend time to work in this area. It is not the same as in physical or tactical situations. It is different."
Emmanuel Adebayor, given a surprise start over Roberto Soldado and Harry Kane, who scored a hat-trick in the Europa League in midweek, headed Tottenham ahead as they dominated the first half.
But Sammy Ameobi was able to score just eight seconds into the second period, before Pochettino had even returned to his seat, and then Ayoze Perez grabbed his first goal for the Magpies.
And Pochettino admitted: "It was a shock because after that it all changed in this moment.
"Seven or six seconds before, all was happiness and there was good energy in the stadium. Our supporters were happy and believed that we would get a good result.
"But in this moment, I think it was difficult to manage in our head. Our heads had gone and we started to take rash decisions on the pitch.
"It was difficult, because 12 or 14 minutes later, we conceded again another goal. At 2-1, it was difficult."