Antonio Conte acknowledged Tottenham's confidence was "killed" after again conceding the first goal in their 2-0 defeat by Aston Villa.
Spurs began 2023 with only a second loss in their last nine matches played on New Year's Day, as second-half goals from Emiliano Buendia and Douglas Luiz gave the visitors all three points at the Tottenham Hotspur Stadium.
Tottenham, who missed the chance to return to the top four, have now conceded the opening goal in each of their last seven Premier League matches, doing so for the first time since November 2010.
They have also now conceded at least twice in seven consecutive league matches for the first time since November 1988 (a run of eight games).
Conte was missing the likes of Richarlison, Dejan Kulusevski and Rodrigo Bentancur for Sunday's visit of Villa, and the Italian feels the lacking of a creative spark was detrimental for his side.
"In the first half, we played with good intensity," he told BBC. "We didn't concede anything, and we found a team that defended too deep. Then, we conceded this goal and then the confidence dropped for my players.
"We have to know that our life is this. We have to fight every game for one point or for three points. This is the truth, especially when you are without two or three important players and have difficulties.
"We have different characteristics. We don't have many players who are really good at beating the man. We don't have many creative players in our team. For sure, today was really difficult to find space in the first half.
"I'm sure that if we don't concede the goal, we could win the game instead. The goal that we conceded killed us in confidence and in many situations for sure. You have to try and improve and develop these players to be even stronger.
"We have conceded the first goal, and we try to play to score goals. We understand very well that the league will be really difficult for us.
"We have to try to recover all the [injured] players, and then we have to know that in every game, we have to fight and show that we are strong."
Tottenham return to action on Wednesday with a trip to London rivals Crystal Palace.