Adama Traore struck to boost Wolves’ survival hopes and deliver a damaging blow to Tottenham’s Champions League dream.
The forward’s first goal since October eased relegation fears at Molineux as the hosts bagged a gritty 1-0 win.
Pedro Porro and Son Heung-min hit the crossbar but Spurs sank to a disappointing defeat on the eve of manager Antonio Conte’s comeback.
Conte will return on Sunday after recovering from gallbladder surgery to a side fourth in the Premier League but low on confidence and struggling to find their killer instinct.
Victories over West Ham and Chelsea had hauled them into the Champions League spots, but a scrappy defeat at Molineux only showed their fragility – following the midweek FA Cup exit at Sheffield United.
Having played two games more than the chasing pack, their fourth spot looks anything but secure.
AC Milan arrive for Wednesday’s last-16 second-leg tie holding a 1-0 advantage and the Italians will fancy their chances of progressing if Saturday’s uninspiring performance is anything to go by.
“It was a good performance,” insisted assistant manager Cristian Stellini. “We started well in the game. The first half was under control, we had chances to score and we could've killed the game.
“We didn't and in the second half the game was more in balance. They found the goal 10 minutes until the end. We did not have the possibility to draw the game.
“It was a tough game like we expected but we were ready to challenge, to fight, to play a great game. We missed some chances in the first half and maybe it could've been a bit different.”
In contrast, positivity is plentiful at Molineux after the hosts moved five points clear of the relegation zone.
After three winless games, fears had grown Wolves would be sucked back into the drop zone, but a gutsy victory gives them further breathing space.
“When you suffer a lot for the team, when you run a lot for the team, when everyone is giving 100 per cent for the team it's a relief,” said Wolves captain Neves.
“We worked really hard to get the three points today. Fortunately we have some time to rest now, some massive games ahead.
“Congratulations to all the players, all the fans and all the staff. Today was about believing about ourselves in the second half.”
The only disappointment for Wolves was Diego Costa being stretched off after landing awkwardly after 28 minutes, adding to worries of a serious injury.
Before that Spurs had been on top, with Jose Sa claiming Son’s shot and turning Dejan Kulusevski’s curling effort wide.
It was still attritional rather than flowing at a subdued Molineux, with stoppages to tend to injuries to Max Kilman and Ben Davies stunting the game’s momentum.
Tottenham still created the best moments of a fairly forgettable first half and, when Ivan Perisic met Son’s deep free-kick, Sa shovelled his header behind.
Son blazed over after Harry Kane’s quick free-kick – his blushes spared by an offside flag – before the visitors went closer in stoppage time.
Perisic’s burst forward was halted by Ruben Neves and Porro curled a 20-yard free kick against the bar.
Just 90 seconds after the restart Spurs rattled the woodwork again when Son’s rising drive, after Kane’s pass, smacked the bar.
The near miss stirred Wolves into life and Nelson Semedo narrowly missed Raul Jimenez’s cutback as the hosts found the urgency which they so sorely lacked.
Traore, on for Pedro Neto at the break, threatened his usual chaos and it was his cross which found Jimenez, only for his header to be parried by Fraser Forster.
Neves twice tested the goalkeeper from distance and Matheus Cunha should have done so much better than shoot wide after Jimenez and Joao Moutinho combined.
Wolves had upped the tempo since the break and finally found the breakthrough with eight minutes remaining.
Jimenez engineered space on the edge of the box and, when Forster parried his drive, Traore’s first-time volley arched over the goalkeeper and dropped in off the bar.