Substitute Dele Alli scored from the spot as Tottenham secured a place in the Europa League knockout stages despite LASK earning a late 3-3 draw.
Alli’s penalty, after Johannes Eggestein had levelled with six minutes left, looked to have won it – only for Mamoudou Karamoko to curl in late on.
Gareth Bale had earlier also scored from the penalty spot following Peter Michorl’s opener for the Austrians.
Son Heung-min then put Spurs ahead before the late flurry of goals.
Tottenham are through with a game to spare but will need to beat Royal Antwerp at home next week if they are to progress as group winners.
Spurs’ fringe players fail to shine
With the north London derby against Arsenal on Sunday, Jose Mourinho made eight changes to the side that drew 0-0 at Chelsea, but Alli and Harry Winks were still only on the bench.
Those given their chance did little to impress and a sluggish start on a freezing evening in Linz meant a string of saves from Hart were needed to keep the side sitting second in the Austrian Bundesliga at bay.
LASK’s pressure eventually told as the hosts broke following Matt Doherty’s slip and Michorl’s long-distance effort beat former England number one Hart down to his left.
Tottenham struggled to string a pass together before their first move of note saw Tanguy Ndombele’s shot hit Andres Andrade’s arm and Bale converted from the spot for his second Spurs goal since returning on loan from Real Madrid.
Two of the three players who kept their places from the goalless draw at Stamford Bridge then combined to put Spurs ahead as Ndombele seized on an error in the LASK midfield to slide Son in on goal.
Bale and Son turned the game in Jose Mourinho’s side’s favour and almost combined for a third, only for the Wales forward to place his pass behind the South Korean.
Alli has found himself out of favour under Mourinho this season and has only featured twice in the Premier League.
The 24-year-old did get his chance with eight minutes remaining but LASK were level moments later when Eggestein, who hit the post in the first half, beat Hart from the edge of the box.
Alli proved he was able to keep his nerve as he put the hosts in front again from the spot with four minutes to play.
But LASK deserved to take at least a point from the game and they got it when Karamoko fired in a dramatic third in the 93rd minute.
- 6WiesingerBooked at 86mins
- 30AndradeBooked at 45mins
- 10MichorlBooked at 32mins
- 17GruberSubstituted forReiterat 69′minutes
- 27GoigingerSubstituted forKaramokoat 69′minutesBooked at 79mins
- 6D Sánchez
- 18Lo CelsoSubstituted forDierat 71′minutes
- 9BaleSubstituted forAurierat 82′minutes
- 28NdombeleSubstituted forBergwijnat 65′minutes
- 27Lucas MouraBooked at 25minsSubstituted forSissokoat 65′minutes
- 7Son Heung-MinSubstituted forAlliat 82′minutesBooked at 88mins
Match ends, LASK 3, Tottenham Hotspur 3.
Second Half ends, LASK 3, Tottenham Hotspur 3.
Goal! LASK 3, Tottenham Hotspur 3. Mamoudou Karamoko (LASK) right footed shot from outside the box to the bottom right corner. Assisted by Reinhold Ranftl.
Dele Alli (Tottenham Hotspur) is shown the yellow card.
Mamoudou Karamoko (LASK) wins a free kick in the defensive half.
Foul by Eric Dier (Tottenham Hotspur).
Goal! LASK 2, Tottenham Hotspur 3. Dele Alli (Tottenham Hotspur) converts the penalty with a right footed shot to the centre of the goal.
Philipp Wiesinger (LASK) is shown the yellow card for a bad foul.
Penalty conceded by Philipp Wiesinger (LASK) after a foul in the penalty area.
Penalty Tottenham Hotspur. Steven Bergwijn draws a foul in the penalty area.
Foul by James Holland (LASK).
Dele Alli (Tottenham Hotspur) wins a free kick in the defensive half.
Attempt blocked. Johannes Eggestein (LASK) right footed shot from outside the box is blocked.
Goal! LASK 2, Tottenham Hotspur 2. Johannes Eggestein (LASK) left footed shot from outside the box to the bottom left corner. Assisted by Andrés Andrade.
Substitution, Tottenham Hotspur. Serge Aurier replaces Gareth Bale.
Substitution, Tottenham Hotspur. Dele Alli replaces Son Heung-Min.
Attempt blocked. Dominik Reiter (LASK) right footed shot from outside the box is blocked.
Mamoudou Karamoko (LASK) is shown the yellow card for a bad foul.
Foul by Mamoudou Karamoko (LASK).
Pierre-Emile Højbjerg (Tottenham Hotspur) wins a free kick in the defensive half.