Mauricio Pochettino says his Tottenham side lacked the energy to match Ajax in the first leg of their Champions League semi-final.
The Dutch outfit will take a 1-0 advantage back to Amsterdam for next week's second leg thanks to Donny van de Beek's first-half goal at Spurs' new stadium.
Pochettino's side, who have now lost consecutive games at their new home having held a 100 per cent record there before defeat to West Ham on Saturday, looked off the pace and nervous for the majority of the first half.
The introduction of Moussa Sissoko following a concerning head injury to Jan Vertonghen gave Spurs more of a say in the midfield battle and brought them back into the tie.
However, after Ajax were afforded the weekend off prior to their London trip - with an entire gameweek of Eredivisie football moved to accommodate their European push, Pochettino was left bemoaning his side's energy levels.
"I think we didn't find a way to play, the team didn't show the energy that we wanted to show," he said.
"I think they showed more energy than us. I think the way that we conceded the goal was so painful.
"We were so poor in this action and in the first half hour of the game we struggled because they showed more energy, they were more proactive than us. That was the key.
In Pictures | Tottenham vs Ajax, Champions League | 30/04/2019
"I think after 30 mins we start to equalise the game. Of course with Sissoko in, we started to play better, we started to show more energy. But of course we started to play better and the second half was much, much better.
"We pushed them to play deeper and we started to press in the way that we wanted to press. We started to play more and I think the second half gives us hope for the second leg in Amsterdam."
Ahead of the second leg in the Netherlands next week, Tottenham will face Bournemouth in the early Premier League kick-off on Saturday.
Ajax, meanwhile, must play the final of the Dutch Cup against Willem II on Sunday night.
