Dango Ouattara scored a dramatic stoppage-time winner to give Bournemouth a shock 3-2 win at Tottenham that severely dents their hopes of a top-four finish.
Arnaut Danjuma's first league goal for Tottenham in the 88th minute looked to have rescued a 2-2 draw for Spurs.
But Outarra's fine finish in the 95th minute - moments after Richarlison was close to scoring a winner for the hosts - gave the Cherries a first victory at Tottenham in the Premier League and moved them six points clear of the relegation zone.
- How the teams lined up | Match stats | Premier League table
- How to watch free Premier League highlights
- Get Sky Sports | Download the Sky Sports App
Heung-Min Son had given Spurs a 14th-minute lead before Bournemouth produced a stunning comeback thanks to Matias Vina's dinked equaliser (38) and Dominic Solanke's composed finish six minutes into the second half.
The damaging defeat means Tottenham stay fifth and remain three points off the top four. Fourth-placed Manchester United have two games in hand, and third-placed Newcastle one game with the Magpies hosting Cristian Stellini's side next Sunday, live on Sky Sports.
How Bournemouth won a topsy-turvy game
Following Aston Villa's thumping 3-0 win over Newcastle, Tottenham had been given extra incentive for the game against Bournemouth, although kick-off was delayed by 15 minutes after the away side arrived late due to traffic.
Tottenham made a fast start as Son scored in back-to-back games, finishing low from Ivan Perisic's cut-back.
Son looked in the mood for a fourth goal in five matches but he was well denied by Bournemouth goalkeeper Neto from a tight angle.
But Spurs were unsettled when the injured Clement Lenglet was replaced by Davinson Sanchez as Pedro Porro gave the ball away from Sanchez's pass to allow Solanke to set up Vina for a 38th-minute equaliser on his first Bournemouth start.
Sanchez was then involved in Bournemouth's second as Marcus Tavernier turned him inside out before the defender poked the ball into Solanke's path and the striker superbly chipped past Lloris.
Tottenham fans booed Sanchez's next touches and Stellini brought the Colombia defender's 23-minute cameo to an end as he replaced him in the 58th minute with Danjuma.
With Spurs 2-1 down there were chants for chairman Daniel Levy to leave, while the fans also sang their support for ex-boss Mauricio Pochettino as the search for a permanent manager continues.
Those quietened, however, when Danjuma appeared to have rescued Tottenham a point with a powerful low effort from the edge of the box two minutes from the end of the 90.
Spurs came close to grabbing a winner as substitute Richarlison headed wide from a corner in the 94th minute.
The Brazil international was then punished for his miss as Spurs were hit on the break with Solanke teeing up Ouattara, who cut inside and curled home into the bottom far corner to spark wild celebrations in the away end.
Stellini: Individual mistakes are costing us
Tottenham acting head coach Cristian Stellini believes "individual mistakes", not tactics are costing his side.
Asked why Spurs keep dropping deep when leading, he replied: "It's a habit we have. It's not the first time. It's a long time that we do this.
"You have to be perfect in the defensive situation but today we were not so perfect because we allowed them to score with two mistakes.
"This is a problem. It's not a tactical problem because it's an individual mistake."
Questioned about the Sanchez substitution and the fans booing the defender, he responded: "I understand it's a tough moment for everyone and we have to analyse this moment.
"Everyone needs to analyse how important it is to support a player. I take the responsibility for the decisions I make.
"I thought it was too early in the game to use another striker because we were 1-0 up in the first half. After when we were 2-1 down I thought it was the moment Davinson has to [come off].
"It was only a tactical decision. We need to support him because it's a tough moment for him and also for all the team."
O'Neil: We overcame 'tough' late arrival to win 'rollercoaster' game
Bournemouth boss Gary O'Neil was delighted to see his side overcome their late arrival at the ground due to traffic issues to record an "incredible achievement".
"It was tough," he said on the delayed kick-off. "We set off from the hotel as usual. The roads were clear and there was an accident just in front of us so firstly I hope everyone involved is okay. Then unfortunately we were sat without being to move for 55 minutes.
"Then we arrived and people were pushing hard to get us to kick-off at 3.05pm. Obviously I was pushing hard for us to delay it as long as I could because the lads need their normal preparation time.
"I didn't see the rush really so I was pushing hard to get it for safety reasons. Players need their normal prep. We can't afford to lose people because they've not managed to warm up properly.
"Thankfully we delayed it just enough because the performance of the players was excellent. To see out the game against such a good side was an incredible achievement.
"It was a rollercoaster of a last 10 minutes - it was very up-and-down. I've settled down now, will enjoy this evening but I've already switched focus on to how I get the group ready for the next one.
Opta stats: Bournemouth end Spurs away day hoodoo
- Bournemouth have picked up their first ever away league victory against Spurs, having lost all five of their away Premier League games against them before today.
- Tottenham have lost a home Premier League game in which they opened the scoring for the first time since February 2022 vs Southampton (2-3). Indeed, Spurs had won 13 successive matches on home soil in which they had opened the scoring before today.
- Bournemouth have won back-to-back Premier League games in a single season for the first time since January/February 2020. Indeed, the Cherries have won five of their last nine top-flight matches (L4), as many as in their previous 25.
- Ivan Perisic has provided 11 assists for Tottenham in all competitions this season, while the only Premier League player with more assists this term is Kevin De Bruyne (21, before Man City's game with Leicester).
- No player has scored and assisted in more different Premier League games this season than Bournemouth's Dominic Solanke (3).
Tottenham face a huge test of their Champions League qualification credentials when they travel to top-four rivals Newcastle on Sunday April 23, live on Sky Sports from 1pm; kick-off 2pm.
Meanwhile, Bournemouth host West Ham, also on Sunday April 23; kick-off 2pm.
Tottenham's remaining fixtures
April 23: Newcastle (A) - Premier League, kick-off 2pm, live on Sky Sports
April 27: Man Utd (H) - Premier League, kick-off 8.15pm
April 30: Liverpool (A) - Premier League, kick-off 4.30pm, live on Sky Sports
May 6: Crystal Palace (H) - Premier League, kick-off 3pm
May 13: Aston Villa (A) - Premier League, kick-off 3pm
May 20: Brentford (H) - Premier League, kick-off 3pm
May 28: Leeds (A) - Premier League, kick off 4.30pm
Bournemouth's remaining fixtures
April 23: West Ham (H) - Premier League, kick-off 2pm
April 27: Southampton (A) - Premier League, kick-off 7.45pm
April 30: Leeds (H) - Premier League, kick-off 2pm
May 6: Chelsea (H) - Premier League, kick-off 3pm
May 13: Crystal Palace (A) - Premier League, kick-off 3pm
May 20: Manchester United (A) - Premier League, kick-off 3pm
May 28: Everton (A) - Premier League, kick-off 4.30pm