Mauricio Pochettino said Tottenham played with their hearts rather than their heads as they blew a chance to put pressure on Premier League leaders Liverpool with a shock 3-1 home defeat to Wolves on Saturday.
A run of five straight league victories combined with a mini-collapse from Manchester City had left Spurs in second place in the table, six points behind Liverpool going into the weekend matches.
But Tottenham -- who had scored 11 goals in their previous two festive fixtures -- will be bitterly disappointed they did not make it six wins out of six after Harry Kane put them in front during a first half they dominated.
The second half was a different story as Spurs became increasingly ragged and the visitors were rewarded for their never-say-die attitude with goals from Willy Boly, Raul Jimenez and substitute Helder Costa.
"I think the game was under control in the first half," said Pochettino. "Maybe it was easier than we expected in the first half to dominate the game and to play so easy. They played so deep, chasing us. We didn't concede one chance.
"But in the second half I think we started to feel maybe the game was over and when you start to feel the game is over it's tough to play in the way you play.
"You start to decide in the wrong way, you start to play too many long balls and to play more with your heart than your head. We started to spend a lot of energy."
"It's not enough to play 60, 70 minutes," he added. "You need to play your best for 95 minutes. Like today we dropped energy and focus and in the last 20 minutes we conceded three goals."
The first few minutes of the match were scrappy as both teams looked for rhythm but Spurs gradually exerted control, Christian Eriksen and the returning Dele Alli probing for openings around the edge of the box.
Spurs were rewarded for their dominance midway through the first half when the in-form Son Heung-min fed Kane, who marauded forward down the right.
Just before he reached the edge of the Wolves box he checked back onto his left foot and hit an unstoppable shot into the far corner past the despairing Rui Patricio.
But despite their clear superiority, Tottenham were unable to earn vital breathing space and the game remained on a knife-edge as the second half got under way.
The dangerous Adama Traore was substituted by Wolves manager Nuno Espirito Santo with just over half an hour to go but the visitors were seeing more of the ball and the Spurs fans became increasingly edgy as the game wore on.
Wolves, urged on by a sizeable travelling support, disrupted Tottenham's smooth passing game, denying their creative players time on the ball and they pulled level in the 72nd minute when Boly rose powerfully to head home a corner from substitute Joao Moutinho.
Spurs huffed and puffed but could not recapture their rhythm and Kane was booked for diving but it was Wolves who scored again when Jimenez rolled the ball into the bottom corner from the edge of the area in the 83rd minute.
They killed the game the game four minutes later after Spurs were caught in possession and Costa was put through and converted easily.
Nuno, whose side climbed to seventh in the table, said he was proud of the character his team showed, first to stay in the match and then to take the game to their illustrious opponents in the second half.
"I think what we had today was two different halves," he said. "In the first half Tottenham had possession of the ball and controlled the game.
"It was important for us to stay in the game.... In the second half we tried to go for the game and play. It was a very good performance."