Tottenham boss Mauricio Pochettino insists his side must enhance their performances if they are to seal a top-four spot this season.
The Lilywhites were looking comfortable in the match when Spurs striker Emmanuel Adebayor found the net in the 18th minute at White Hart Lane.
And, Newcastle United, who needed a win to move out of the bottom three and send their rivals Sunderland down into the relegation zone, cancelled Adebayor's goal by a strike from Sammy Ameobi after the restart.
Ayoze Perez put Alan Pardew's side ahead in the 58th minute, Tottenham could not find an equaliser and the match ended 2-1, while Pochettino's men slipped down to 11th place in the Premier League table.
“We need to improve a lot [to get in top four]. It’s not tactical or physical it’s our mentality,” Pochettino said after the clash. “It’s a big hit for us.”
The Spurs manager added: “We need to be more strong and to have more focus. Today in the second half, straight from the kick-off we conceded a goal. It’s crazy.”
Pochettino also questioned his team's mental strength after their 2-1 defeat.
“Seven or six seconds before [the first goal], all was happiness and there was good energy in the stadium. Our supporters were happy and believed that we would get a good result,” Pochettino continued.
“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 another goal. At 2-1, it was difficult.”