Sporting Lisbon condemned Tottenham to their first defeat this season as Paulinho's last-gasp goal inspired a shock 2-0 win in the Champions League.
Spurs were contemplating an evening of frustration as it looked like they would be held to a goalless draw in Portugal before things went very wrong in the final moments.
Paulinho nodded home from a corner and then with virtually the last kick Arthur Gomes sauntered into the box to convert and put Sporting top of Group D with two wins from two.
Boss Antonio Conte will be furious with the manner of the loss as his side suffered their first defeat since April in an uninspiring display.
“It’s a difficult result. For sure when you lose the game you’re not happy," said Conte.
"The game was imbalanced in the second half. We tried to win the game and we could have scored and then in the last 10 minutes we can do much better. It’s a pity. We tried to get the winner but in the end we lost the game.”
It had been a slow start, with Marcus Edwards intent on showing his old club what they were missing from the start.
And after a darting run down the channel he laid a chance on for Pedro Goncalves inside the opening 10 minutes, but Hugo Lloris was equal to the low shot and tipped it wide.
Spurs looked threatening in patches and thought they took the lead on the stroke of half-time as Richarlison rounded the goalkeeper after being played through by Harry Kane, but the Brazilian was well offside.
It needed another Lloris save to ensure the visitors went in level as the Frenchman denied Edwards a wonder goal.
The 23-year-old, who Mauricio Pochettino once compared to Lionel Messi, sauntered past a number of challenges to advance into the box, played a one-two, beat another man and then stabbed a shot, but was denied by a fine low stop from the Frenchman.
Spurs started the second half strongly and had enough chances to take control of the game.
Emerson Royal could not connect properly with Kane’s quick free-kick, the England captain then stung the palms of Antonio Adan and Richarlison drifted an effort wide at the far post.
Spurs upped the ante in search of the breakthrough and Kane was just unable to get on the end of a wicked Ivan Perisic cross while Richarlison headed Dejan Kulusevski’s cross wide.
But Spurs were undone in three minutes of injury time.
Paulinho glanced a header home before Arthur produced a moment of brilliance to weave into the area and shoot under Lloris.
Sporting midfielder Edwards, a boyhood Tottenham fan, said after the game: “We put in a hard shift so winning at the end like that feels great. We’ve got to be happy. I think we deserved it.
“It’s a strange feeling playing against Spurs. But I just prepare the same was as I prepare for any other game. I just focus. But of course I want to come back to Spurs one day.”