Callum Wilson's last-gasp strike piled the pressure on Thomas Frank as Tottenham were booed off at half-time and full-time following their 2-1 defeat to relegation-threatened West Ham at the Tottenham Hotspur Stadium.
The game was dubbed 'El Sackico' ahead of the game by former Spurs boss Tim Sherwood because of the pressure on both Frank and Nuno Espirito Santo at West Ham, and it was the visitors who held the early advantage after Crysencio Summerville's 15th-minute goal.
Spurs were second best for the majority of the first half and looked short of ideas before the boos rang out at half-time.
Frank thought his side had rescued a point after Cristian Romero's bullet header (64), but Wilson's stoppage-time strike condemned the hosts to a ninth league defeat of the season and led to Tottenham's South Stand calling for Frank's dismissal.
The final whistle sparked a mass exodus at the Tottenham Hotspur Stadium. The home fans had seen enough but those left started "sacked in the morning" chants aimed at Frank, who was then booed again as he applauded the fans on his way to the tunnel.
On the chants, Frank said: "I've had probably had better times.
"I understand, I'm the man in charge. As long as they back the players to drive them forward, and we will keep going forward."
It was in stark contrast to the West Ham players as they celebrated with their fans after ending a long 10-game winless run in the Premier League as they breathed some life into their bid to beat the drop.
Hammers match winner Wilson said: "It's massive today, the boys played fantastic.
"I think we deserved to be in front on the whole, especially with the chances we had first half. It wasn't to be, but thankfully we ended up getting the three points."
Tottenham manager Thomas Frank on the defeat to West Ham to Your Site:
"It's tough to take, it hurts a lot. The boys put everything in, and that's a sign of a squad that is fighting, doing everything they can to try and win. It's fair to say if there was to be a winner in the second half then it should have been us.
"The way we came back into it, the same as at Bournemouth, both games we lost in the last minute. That makes it emotionally tough for the players, me, the club, the fans, everyone. We conceded on a deflected shot and a last-minute corner, which we should have done better with.
"We pushed very hard, to have that extra freshness to put on the pitch would have helped with more quality.
"It's tough times, the only thing we can do is move forward. We have to go again, it's hurting so much, incredibly so for everyone at the club that puts in such hard work.
"But we can only be disappointed and emotionally down for 24 hours, then we must go again on Tuesday."
Former Spurs boss Tim Sherwood on Soccer Saturday:
"It doesn't look good. Spurs cannot win a game at home and they have lost to their local rivals, who appear doomed at the bottom of the Premier League.
"The pressure is on Frank. But the only thing that might save his job is who could come in?
"They won a trophy last year and finished 17th. They aren't going to win a trophy this year. They are out of both cups and towards the bottom of the league. They are still in the Champions League but it is highly unlikely they win that.
"Where do Spurs go from here?"
West Ham manager Nuno Espirito Santo on his side's chances of avoiding relegation after victory at Spurs:
"It means a lot for our fans, who were there cheering for us. It's special to do it in the last moments of the game, because we have been on the other side of that many times this season.
"We stared really well. The way we were organised, not allowing Spurs to go easy, always trying to press and recover.
"When we had the ball we had good chances and combinations. First half we played really good football.
"We believe [we can escape relegation]. We have to worry about ourselves, work harder and commit more. I'm really proud of the way the players have been dealing with this situation. It's a tough one, but they are determined to turn it around."
Spurs have now lost 50 games in all competitions at the Tottenham Hotspur Stadium, with their first also coming against West Ham.
They've played 176 games at the ground, with their last 50 defeats at White Hart Lane coming over a 295-game spell between 2006 and 2017.
Tottenham have lost more games thanks to 90th minute winning goals than any other side in Premier League history (29), with this the first time they've done so in consecutive matches in the competition.
West Ham have now conceded in each of their last 19 Premier League games, since a 3-0 win at Nottingham Forest in August. It's their longest run without a clean sheet within a single season in the competition.
