Tottenham boss Ange Postecoglou said their 3-2 loss at Brighton was the "worst defeat" of his Spurs managerial tenure and blasted his side for their lack of fight in their capitulation at the Amex Stadium.
Tottenham suffered a second-half collapse on the south coast as Brighton scored three goals in 18 minutes to come from 2-0 down to win 3-2.
Spurs never looked like equalising after Danny Welbeck's 66th-minute strike, leading Postecoglou to claim his side "accepted their fate" as their five-game winning run was shockingly ended.
Brighton 3-2 Tottenham: Match report & highlights
As it happened: How Spurs collapsed on the south coast
Teams | Match stats: Brighton make stunning second-half turnaround
Postecoglou told Sky Sports: "It's disappointing. Frustrated. I'm absolutely gutted with that.
"That's probably the worst defeat we have had since I've been here.
"An unacceptable second half. We weren't anywhere near where we should be. Maybe we got carried away with how we were going.
"We accepted our fate which is hard to understand because we haven't done that since I've been here. We've normally fought for everything. When you don't you pay a price and we paid a price.
"Maybe that's part of the problem, maybe things were travelling on too smoothly. Football and life will trip you up if you get too far ahead of yourself and that's what it looked like to me in the second half."
The stunning defeat leaves Spurs in ninth and four points off the top four heading into the October international break.
Asked what the message is for the players, the Australian responded: "There's no message. It is a terrible loss. As bad as it gets, and there's only one way to fix it and that's my responsibility.
"We lost all our duels, we weren't competitive. If you lose all your duels, irrespective of what you do tactically, it's not going to work. You have to be competitive.
"They all go on international duty, the players will process it individually. I will deal with it when everyone gets back."
Ange: We didn't deserve to get anything out of game
Postecoglou cut a particularly downbeat figure in his post-match press conference.
The 59-year-old said: "There are certain elements of this team that have been pretty consistent throughout my tenure, and that is, even in our not-so-good days, we've always fought and been competitive. I think that's been sort of non-negotiable.
"Today's the first day I actually felt like we didn't deliver in those areas, whether that's defensively, whether that's with the ball.
"Sport's as much about competition as it is anything else, and if you don't compete and you allow the opponent to overrun you in that manner, then you're not going to get anything out of it."
He added: "We didn't do the basics of everything we've done to get to this point, good, bad, or otherwise.
"So even when we didn't win at Newcastle, we played well, and we fought hard to the last second to try and win that game of football. We didn't do that today. And every time we've played, that's been an element of our game where I felt that was in. I didn't see that today."
Questioned whether he had learned something new about his team, he responded: "I don't know if I learned something new, but I certainly experienced something new, which with all these things, straight after a game you're emotional about it.
"That's probably the most disappointing loss I've had since I've been here in terms of the way we went about it, and it's something I need to assess."
Asked whether he could have made substitutions before Brighton's second and third goals, he replied: "Yeah, I could have, but all these things are totally irrelevant to me, substitutions and all those kind of things.
"If you're not competitive, it doesn't matter what you do, you're not going to get rewards. You don't deserve to win. So we didn't deserve on our second-half performance, irrespective of subs or anything else, to get something out of the game.
"But I do think if you do get something out of the game, then you're falsely rewarded, and I don't want to get falsely rewarded."
Maddison: We have to deal with adversity better
Tottenham midfielder James Maddison, who put Spurs 2-0 up after Brennan Johnson's opener, admitted they "lost complete control" after Yankuba Minteh pulled one back in the 48th minute for Brighton.
The England international told Sky Sports: "We couldn't deal with the mental shift and lost complete control of the game after the first goal went in. We dealt with the momentum very poorly. It just felt like attack after attack and we couldn't deal with it.
"Brighton are a good side but when the first goal went in you have to deal with adversity in the Premier League and stay strong, weather the storm. The best teams stay strong. We didn't do that.
"We'll need to take big lessons from the second half if we want to make strides forward."
Berbatov: Spurs are too nice
Tottenham lost a Premier League game in which they had led by two or more goals for the 10th time, becoming the first club to hit double figures for this, and at least three more than any other side in the competition's history.
Dimitar Berbatov believes his former club remain a soft touch under Postecoglou.
The ex-Spurs striker told Sky Sports: "This type of stuff happened to Spurs before and continues to happen.
"They have a couple of good games but then it all comes crashing down because of results like that or something else.
"This is where they need to be mentally strong [after conceding the first goal], weather the storm, but it didn't happen for Spurs. If you don't have consistency in your performances to stay at the top you are going to suffer.
"Spurs are too nice."
Meanwhile, another ex-Spurs striker, Les Ferdinand, believes the players should be "embarrassed" by their collapse.
"The players will be getting on that coach embarrassed," he told Sky Sports.
"The fans have turned up in their numbers and have been embarrassed by the second-half performance.
"That's what you're left with as a player, embarrassment and humiliation. That lingers until you play again."