It was a poor start to the game for the Cherries as they fell behind early on to a Mathys Tel goal, but they turned the game around before the break.
Evanilson drew them level with an excellent glanced header, before Junior Kroupi put the hosts in front nine minutes before the interval.
The second half was a scrappier affair, and, not long after Spurs had a penalty decision overturned by VAR, the visitors drew themselves level.
Joao Palhinha fired an overhead kick past Djordje Petrovic after the ball was allowed to bounce in the box from the second phase from a corner.
But Semenyo had the final say in perhaps the final few minutes of his Cherries career before a potential move to Manchester City.
On his 26th birthday, the Ghanaian smashed the ball home from just outside the box deep into stoppage time.
(Image: Richard Crease)
That gave the Cherries their first win since the end of October, ending a run of 11 games without a win, and sealed their first-ever league double over Spurs.
Andoni Iraola made two changes to his side which lost to Arsenal, with Kroupi coming in for the injured Justin Kluivert, while Lewis Cook replaced David Brooks, who dropped to the bench.
Antoine Semenyo started in potentially his final game for the Cherries ahead of a move to Manchester City.
Bournemouth had the worst possible start as they trailed five minutes.
It was a poor goal to concede, after a good backheel from Xavi Simons found Tel in space on the left, he cut inside James Hill before shooting and it crept past Djordje Petrovic and in at the far post.
Mathys Tel gave Spurs the lead. (Image: Richard Crease)
The Cherries sought a response and went close through Marcus Tavernier, who shot just wide from range, before Kroupi put an effort just wide at full stretch.
Cristian Romero flicked a header onto the roof of the net from a corner for the visitors, before the hosts drew themselves level.
Bournemouth won back-to-back corners as they sought to inject some energy into their attack, and they went close from the second, as Evanilson was not far away from an Alex Scott cross.
But the hosts recycled the ball and Tavernier delivered a superb cross from the right for the Brazilian to rise and guide the ball home at the far post with his head.
Pedro Porro blasted a shot well over the bar, before Lucas Bergvall curled a good effort just over the top.
The Cherries were in front with 36 minutes on the clock as they turned the game around in the first half.
Junior Kroupi netted his seventh goal of the season to give the Cherries the halftime lead. (Image: Richard Crease)
Another excellent cross from Tavernier on the right was just missed by Semenyo and it went all the way through to Marcos Senesi, who cut the ball back across goal for Kroupi to finish for his second goal in as many games.
Bergvall had a go from a tight angle on the right as he shaped to cross but spotted Petrovic off his line, but the Serbian was equal to it as the Cherries led at the break.
It was a scrappy start to the half with chances few and far between for both sides.
Iraola went to his bench shortly after the hour mark and replaced both first half goalscorers, with Enes Unal and Brooks introduced for Evanilson and Kroupi.
Alex Jimenez (Image: Richard Crease)
Unal struck the defensive wall from a free kick 25 yards out with his first touch of the night, before Richarlison struck the post with a header after Romero headed a corner back across goal.
The Turkish striker had a good chance to extend the Cherries lead after a drilled Semenyo cross from the left was cut out and fell to Unal, but he shot wide.
Spurs were awarded a penalty with a little over 15 minutes to play after Micky van de Ven went down in the box after a driving run.
But referee Darren England was sent to the screen by the VAR and determined that there was no foul, as van de Ven appeared to jump into the challenge of Hill as the centre back pulled out, and the Spurs man was booked for diving.
Semenyo’s parting gift: Stoppage time goal sees Cherries defeat Spurs (Image: Richard Crease)
But Tottenham were level with 12 minutes to play.
A corner from the right was headed straight up into the air and was allowed to bounce, and Palhinha finished acrobatically with an overhead kick.
Petrovic denied van de Ven with an excellent save, before Bafode Diakite and Amine Adli replaced Tavernier and Jimenez.
Brooks shot over the bar, before Semenyo smashed home a winner to send the Dean Court crowd into pandemonium.
The Ghanaian picked the ball up on the left from Brooks, and took a couple of touches before smashing home into the bottom corner past Guglielmo Vicario.
Semenyo was then replaced by Veljko Milosavljevic to a huge ovation as the Cherries then held on to their lead to return to winning ways and end their poor run without a win.
AFC Bournemouth: 1, D. Petrovic; 3, A. Truffert, 5, M. Senesi; 23, J. Hill; 20, A. Jimenez (booked, 77’)(Adli 87’); 4, L. Cook (c)(booked, 51’); 8, A. Scott; 24, A. Semenyo (booked, 43’)(Milosavljevic 90+10’); 22, J. Kroupi (Brooks 64’); 16, M. Tavernier (Diakite 87’); 9, Evanilson (Unal 64’).
Tottenham Hotspur: 1, G. Vicario; 24, D. Spence; 37, M. van de Ven (booked, 75’); 17, C. Romero (c); 23, P. Porro (booked, 60’); 30, R. Bentancur (Gray 86’); 6, J. Palhinha; 11, M. Tel; 7, X. Simons; 15, L. Bergvall (Odobert 57’); 39, R. Kolo Muani (booked, 61’)(Richarlison 67’).