Lucas Moura believes Spurs lacked intensity and desire in their 2-1 defeat at Arsenal on Sunday.
Tottenham largely played the north London derby on the back-foot, allowing the Gunners to dominate possession and create far more chances.
Spurs ironically only got a foot in the game in the last 15 minutes following Erik Lamela's dismissal, with Harry Kane having a late equaliser ruled out for offside and Davinson Sanchez having an effort cleared off the line in stoppage time.
Lucas, who was one of few Spurs players to have played well on Sunday, admitted that the team performance was well below the standards they have set lately.
"In the game against Arsenal, I think we didn't play at our level," he said, speaking ahead of Tottenham's Europa League tie with Dinamo Zagreb.
"We didn't do well. The last few games, we did very well. Against Arsenal, I think we started low with no intensity. We were too passive in the game and it cannot happen."
Spurs looked like they had turned a corner following big wins against Wolfsberger, Burnley and Crystal Palace, and Lucas pinpointed the difference between those performances and the one at the Emirates.
"The difference between that game and the other three games I think was the intensity and the desire," he added. "It can't happen, but it is in the past now. We have another important game tomorrow and you need to focus on that game."
That Lucas, a player Jose Mourinho earlier said he does not have to worry about in terms of match preparation, admitted that a team chasing a Champions League spot and silverware were not able to match intensity and desire in one of Europe's biggest derbies will surely be worrisome news for Spurs fans.
Tottenham now sit eighth in the Premier League table, six points off the top four, and may have to rely on winning the Europa League in order to qualify for the Champions League.
Source : 90min