Rodrigo Bentancur's equaliser ensured Spurs avoided a third successive defeat in all competitionsTottenham will need at least a draw in Marseille in their final Champions League group game to secure a place in the knockout phase after being denied victory in a dramatic finale against Sporting Lisbon.
Spurs knew victory would guarantee a place in the last 16 but they laboured for long periods before being denied a last-gasp winner when Harry Kane's strike was ruled out for offside with manager Antonio Conte shown a red card in the ensuing chaos.
In a tense encounter, former Spurs youngster Marcus Edwards gave Sporting a deserved 22nd-minute lead with a fine low shot as they punished Conte's side for a poor first-half display that brought loud jeers from the home fans.
Spurs were much improved after the break but they were grateful to a crucial save by keeper Hugo Lloris from Sporting substitute Flavio Nazinho, who also shot wide with the goal at his mercy.
They took advantage of those two escapes as Rodrigo Bentancur rose to head home from a corner 10 minutes from time - and in a hectic finish both sides had opportunities to win.
Kane thought he had snatched it with virtually the last kick - only for VAR to decide otherwise.
Spurs pay for slow start
Spurs were left regretting the intervention of VAR that denied them the win but they must also rue another slow start that allowed Sporting to take control for the first 45 minutes.
The increasingly rebellious mood inside the Tottenham Hotspur Stadium was reflected in the angry reaction from supporters who had grown frustrated at a series of aimless and misplaced passes allied to a lack of urgency.
It was all so different after the break as Spurs came to life, finally applying pressure on Sporting and forcing keeper Antonio Adan into action.
They still looked vulnerable, however, and Lloris - rightly criticised for his errors in the home defeat against Newcastle United on Sunday - came to the rescue with that crucial save from Nazinho, although the Sporting forward should have made no mistake with a second chance which he steered wide of an open goal.
Spurs, having got themselves back into the game, had chances to get the three points that would have made the trip to Marseille a formality but Eric Dier and Bentancur could not find the target.
The game ended in a melee, with Conte being sent off after wildly celebrating what he thought was the goal that secured the knockout place when Kane swept home Emerson Royal's knockdown.
Spurs have work to do in Marseille and they must learn the lessons of being punished for leaving it late to kick into gear.
Edwards shows his quality
It was perhaps inevitable that Marcus Edwards would score on his return to Spurs, the club where he could not make the breakthrough despite his talent.
The 23-year-old is fulfilling his potential in Lisbon and followed up a fine performance in the first group game, which Sporting won 2-0, with another display rich in promise here.
He was a constant threat until he faded after the break, threatening several times in the first half and giving Sporting the lead with a low short drilled beyond Lloris as Spurs paid the price for standing off.
Edwards is now bolting on attitude to ability and will have impressed all observers, and those who remember him from his unfulfilled Spurs career, with how he performed here.
The four teams in Group D are separated by two points going into the final round of fixturesPlayer of the match
EdwardsMarcus Edwards
Sporting Lisbon
Squad number10Player nameEdwards
Squad number82Player nameMateus Fernandes
Squad number20Player namePaulinho
Squad number11Player nameNuno Santos
Squad number24Player namePorro
Squad number17Player nameTrincão
Squad number5Player nameMorita
Squad number71Player nameFlávio Nazinho
Squad number2Player nameMatheus Reis
Squad number15Player nameUgarte
Squad number4Player nameCoates
Squad number1Player nameAdán
Squad number25Player nameGonçalo Inácio
Squad number18Player nameFatawu
Squad number3Player nameSt. Juste
Squad number33Player nameArthur Gomes
Line-ups
Tottenham
Formation 3-4-2-1
1Lloris
17Romero15Dier33Davies
2Doherty5Højbjerg30Bentancur14Perisic
27Lucas Moura7Son Heung-Min
10Kane
1Lloris17RomeroBooked at 67mins15Dier33DaviesSubstituted forLengletat 81'minutes2DohertySubstituted forGilat 71'minutes5Højbjerg30Bentancur14Perisic27Lucas MouraSubstituted forEmerson Royalat 82'minutes7Son Heung-Min10KaneSubstitutes
4Skipp6D Sánchez11Gil12Emerson Royal19R Sessegnon20Forster24Spence25Tanganga29Sarr34Lenglet38Bissouma42WhiteSporting
Formation 3-4-2-1
1Adán
25Inácio4Coates2Reis de Lima
24Porro15Ugarte5Morita11Gomes dos Santos
10Edwards17Machado Trincão
20Dias Fernandes
1Adán25Inácio4CoatesBooked at 41mins2Reis de Lima24Porro15UgarteBooked at 83mins5MoritaSubstituted forEspanha Fernandesat 61'minutes11Gomes dos SantosSubstituted forBasilua Jacinto Názinhoat 62'minutes10EdwardsSubstituted forFatawuat 71'minutes17Machado TrincãoSubstituted forGomes Lourençoat 71'minutes20Dias FernandesSubstituted forSt. Justeat 75'minutesSubstitutes
3St. Juste6Alexandropoulos12Israel16Costa Rocha18Fatawu22Eusébio Paulo33Gomes Lourenço63Martinez Marsà71Basilua Jacinto Názinho77Borges Cabral82Espanha Fernandes84EssugoReferee:Danny MakkelieAttendance:59,588Live Text
Match ends, Tottenham Hotspur 1, Sporting Lisbon 1.
Second Half ends, Tottenham Hotspur 1, Sporting Lisbon 1.
VAR Decision: No Goal Tottenham Hotspur 1-1 Sporting Lisbon.
GOAL OVERTURNED BY VAR: Harry Kane (Tottenham Hotspur) scores but the goal is ruled out after a VAR review.
Offside, Tottenham Hotspur. Emerson Royal tries a through ball, but Harry Kane is caught offside.
Attempt missed. Pedro Porro (Sporting Lisbon) right footed shot from outside the box is too high. Assisted by Manuel Ugarte.
Foul by Emerson Royal (Tottenham Hotspur).
Flávio Nazinho (Sporting Lisbon) wins a free kick in the defensive half.
Cristian Romero (Tottenham Hotspur) wins a free kick in the defensive half.
Foul by Mateus Fernandes (Sporting Lisbon).
Attempt missed. Rodrigo Bentancur (Tottenham Hotspur) right footed shot from the centre of the box is too high. Assisted by Bryan Gil.
Attempt saved. Son Heung-Min (Tottenham Hotspur) left footed shot from outside the box is saved in the bottom right corner. Assisted by Bryan Gil.
Offside, Tottenham Hotspur. Pierre-Emile Højbjerg tries a through ball, but Son Heung-Min is caught offside.
Corner, Sporting Lisbon. Conceded by Hugo Lloris.
Attempt saved. Issahaku Fatawu (Sporting Lisbon) left footed shot from outside the box is saved in the bottom left corner.
Attempt missed. Eric Dier (Tottenham Hotspur) header from very close range misses to the right. Assisted by Clément Lenglet.
Foul by Ivan Perisic (Tottenham Hotspur).
Pedro Porro (Sporting Lisbon) wins a free kick in the defensive half.
Offside, Sporting Lisbon. Pedro Porro tries a through ball, but Arthur Gomes is caught offside.
Attempt missed. Eric Dier (Tottenham Hotspur) header from very close range misses to the left. Assisted by Son Heung-Min with a cross following a set piece situation.
