Tottenham manager Mauricio Pochettino has claimed "lack of concentration made all the difference" during disappointing 2-1 defeat against Newcastle on Sunday 26 October.
Spurs controlled the game in the first-half and took the lead through Emmanuel Adebayor.
However, Newcastle Sammy Ameobi equalised just 10 seconds into the second half before Ayoze Perez complete the overcome with his first Premier League goal.
"Newcastle is a big team but when you analyse the game, after 45 minutes it is impossible to say we are going to concede a goal like that," Pochettino said after the game.
"I think it was the best 45 minutes we have played. It was a lack of concentration which made all the difference."
Spurs have just one win in their last seven league games while secure their third defeat of the season at White Hart Lane.
The manager claimed they deserved to go to the half-time with a bigger difference and does not understand how eventually they let Newcastle to come from behind in a horrible second half.
"We need to analyse the first half, it was very good, we deserved more than the one goal. It is difficult to explain how we started the second half, it was a stupid goal.
"It was a shock, all changed after this moment, six second before the stadium had good energy but after this moment our head had gone."
Pochettino insists the lack of concentration made the difference and claim they need to recover the winning mentality as soon as possible.
"It was a lack of concentration for us and we need to work on our mentality because it is not a physical or a tactical thing. It is our mentality and our challenge to improve,"
"We need to be stronger like a team. We need to speak and create a different situation on the training ground. We need time to work in this area."