Mauricio Pochettino says the early goal Tottenham conceded in Wednesday's Champions League group match destroyed their hopes of beating Barcelona and described his players as "heroes" for getting back within one goal of the Catalans.
Philippe Coutinho put the visitors ahead inside the opening two minutes at Wembley, following mistakes from Kieran Trippier and Hugo Lloris, and Ivan Rakitic made it 2-0 before the break.
Spurs twice rallied, making it 2-1 and then 3-2 and nearly equalising with a deflected Lucas Moura effort, but Lionel Messi's 90th-minute strike -- his second goal of the night -- ended Spurs' hopes.
"To concede, I think all the plan was destroyed," said Pochettino. "It's so difficult afterwards to assess. The first half was difficult for the team to start to play and feel confident in the way that we planned to play because of a few mistakes before the action that we conceded.
"Those who play football understand completely that if you start that way in this type of game, in a Champions League game against a team like Barcelona, you cannot concede these types of chances.
"But for me the most important thing was that in the second half we played and we showed character. We were competitive and always we were in the game. We did everything to try to come back and I feel proud of the effort of the players tonight.
"After 45 minutes, Lionel Messi, I don't think we conceded one chance to him. Of course in the second half when we are 2-0 down you are going to give more space and we were more attacking and it's so difficult to stop this kind of player.
"In the second half, with a lot of space, it's unbelievable how much he ran and dribbled and the possibilities to score, but come on. Move on because in the first half we conceded in the first minute and we cannot talk about topics.
"I think our players were heroes because to chase the game, playing against Messi, Suarez, Coutinho and company, and be competitive in the second half... If Lucas Moura scored the third goal sure we talk about we are heroes and the manager is the best in the world.
"It was 4-2 of course for Barcelona but the team did everything and I feel so proud about their performance."
The pitch at Wembley was in a poor state, 11 days after the stadium hosted Anthony Joshua's heavyweight boxing match against Alexander Povetkin, and Spurs must play on the surface again on Saturday when they host Cardiff.
"I think for both teams the pitch wasn't great," said Pochettino. "But I think for Barcelona it was worse because in the history of football Barcelona always try to play along the grass. I'm not going to complain about the pitch.
"Of course you understand that it wasn't in the plan to play this type of game in this period at Wembley. What can we do? Nothing, because the period the grass needs to grow is more time than we gave because the boxing was here [just over] 10 days ago. It's impossible to put it in better condition for today and Saturday of course."
Spurs are still without a point in their Champions League group, having lost both of their matches so far against Inter Milan and Barcelona.
"We still need to play four games and we are going to have it in our hands to be or not in the next stage," said Pochettino. "It will be tough because we've got to win the games. We're still thinking the same, though, that all is possible."