Spurs seemed to be in complete control of this game and closing in on Leicester when West Brom’s Craig Dawson scored an own goal in the 33rd minute.
But the same player equalised for the visitors with 17 minutes remaining and Mauricio Pochettino’s men could not find the winning goal they desperately craved.
It means that with three games to play, Tottenham are now seven points behind Leicester, who can secure the title if they win at Manchester United on Sunday.
And there could be worse news to come for Spurs, with Dele Alli facing retrospective action and a possible three-match ban for an off-the-ball incident, involving Cladio Yakob.
Alli appeared to punch the West Brom midfielder in the stomach, and although referee Mike Jones took no action, TV cameras caught the incident.
If it is reviewed, by the FA, Alli could face a charge of violent conduct, which would bring a three-match ban and rule him out of Tottenham’s remaining games.
On the final whistle Spurs players looked distraught, some punching the turf in frustration knowing that they have now given themselves too much to do.
“We’ve got to keep fighting but it’s a big blow — we felt like we had to win all our games,” Harry Kane said.
“We’ve got to dust ourselves down and see if Man United can do us a favour. There’s nothing we can do about it, we’ll keep fighting.”
Yet it had all looked so straightforward for Spurs in a first-half that was so one-sided it resembled a training ground exercise, with West Brom the defenders and Tottenham given the task of trying to break them down.
Pochettino’s men went about their task with vim, vigour and no little style. Christian Eriksen had a dipping free-kick tipped away in the fourth minute after the first of a rash of fouls on Alli, the newly-crowned young player of the year.
Eriksen and Alli combined to send Harry Kane through, and the England striker hit his shot firmly but too close to Boaz Myhill, who was able to divert the ball on to the inside of the far post and out again.
When Danny Rose was fouled on the edge of the penalty area, Eriksen tried his luck again and went closer, shaving the top of the crossbar from 25 yards.
A huge part of Kane’s success has been his willingness to shoot at goal and he tried a low drive that Myhill did well to get across and tip away. Eric Dier headed over the ensuing corner.
It always looked more likely that Tottenham would open the scoring, and so it proved in the 33rd minute, although it was a visitor who put the ball over the line. Eriksen curled in another free-kick, Vertonghen tussled for the ball with Craig Dawson, and as they fell in front of Myhill, Dawson’s arm propelled the ball past the stranded keeper.
It was a lucky break, perhaps, but one Spurs deserved fully. The quality of their play was a delight to watch, if a little frustrating for their supporters as they over-elaborated at times in playing out from the back.
Presumably Tony Pulis had harsh words with his players at half-time because West Brom showed more adventure after the break, and had a sustained period of pressure on the home goal. Huge Lloris was finally called in to action to save a free-kick from Gardner early in the half, and the former Villa midfielder crossed for Salomon Rondon, who put his header wide of the near post.
And when the big striker got a chance to shoot, Lloris had to tip the ball over. Gartdner swung in a corner from the left, Dawson rose above Dier and headed home to the delight of the small band of Albion fans at White Hart Lane.
Dier was hurt in the incident, and had to be replaced by Ryan Mason, with Spurs now desperate.
But the equaliser gave West Brom renewed energy, and they also went for the winning goal, opening the game up. Eriksen fired a free-kick high over the bar, Dembele shot wide of the far post, but there was no way through, and the final whistle brought a mixture of joy for the visitors, despair for the home side and frustration for their fans.
Lloris, Walker, Alderweireld, Vertonghen, Rose, Dier (Mason 75), Dembele, Lamela (Son 85), Alli (Chadli 90), Eriksen, Kane.
Myhill, Dawson, McAuley, Olsson, Evans, Yacob, Fletcher, Sessegnon (Sandro 90), Gardner, McClean, Rondon.
- Jamie Vardy will miss Leicester’s trip to Manchester United after an independent regulatory commission imposed an extra one-match band following the FA charge of improper conduct following his dismissal against West Ham.
Vardy had requested a personal hearing in the hope of leniency following his controversial sending off in the 2-2 draw at the King Power Stadium.
The England striker failed, however, and has also been fined £10,000.