Stade Francais (3) 10
Try: Leguizamon Con: Hernandez Pen: Hernandez
Harlequins (12) 15
Tries: Williams, Turner-Hall Con: Evans Pen: Evans
Turner-Hall races clear to score his side's second try
Harlequins belied their underdog billing to claim a famous away victory over the mighty Stade Francais in Pool Four of the Heineken Cup.
Quins raced into a 12-0 lead thanks to tries from Tom Williams and Jordan Turner-Hall, before a late Juan Martin Hernandez kick narrowed the gap.
A try from Juan Leguizamon cut Quins' lead to 12-10, but the visitors refused to cave in despite intense pressure.
Nick Evans' penalty extended the lead, and Quins held on in a frenetic finish.
A sold-out Stade de France witnessed a no-expense spared pre-match entertainment extravaganza featuring Can-Can Girls and a jousting contest, and the home side seemed inspired with winger Julien Arias inches away from scoring the opening try after a minute.
Soon after, Chris Robshaw got his body underneath the ball as enormous Stade centre Mathieu Bastareaud drove over the try-line.
But Quins weathered the storm and soon it was Stade making nervy mistakes as the visitors took the lead.
The effervescent Danny Care chipped into space and Stade backs Djibril Camara and Julien Saubade made a meal of it, allowing Williams to pounce on the loose ball and score.
Quins were close to a second soon after, but Care lost his footing on the slippery surface as he chased a loose ball that had been hacked forward.
Stade were a pass away from scoring in the corner, but the ball went loose to allow Quins full-back Mike Brown to belt the ball into space at the other end.
Another handling error from Camara gave Turner-Hall possession, and the centre scorched down the touchline to put his side into a 12-0 lead that almost silenced the home crowd.
A missed penalty from Juan Martin Hernandez added to Stade's problems as the whistles started in the stands, and some lovely Harlequins handling kept the home side on the back foot.
But a Sergio Parisse break sparked Stade into life, and Care found himself sent to the bin for cynically killing the ball.
Hernandez kicked the resulting penalty to cut the gap at the break, and Stade began the second half with a much greater sense of purpose.
Camara made a break down the touchline, and a few phases later Stade number eight Leguizamon took a delightful offload from Brian Liebenberg before arcing around the cover to score.
The pre-match entertainment was a little out of the ordinary
Stade began to dominate possession, and Harlequins' defensive abilities were stretched to the limit with a fantastic tackle from Nick Easter on Bastareaud typifying his side's efforts.
A fantastic drive at the scrum gave Care the chance to chip into space once again, and Quins managed to draw a penalty from the isolated Hernandez which the ice-cool Evans struck between the uprights for a five-point lead.
Stade had no choice but to commit all-out to attack, but Quins' defence was something special in an atmosphere more reminiscent of a Test match than a club game.
Two fights broke out in the closing stages as an increasingly desperate Stade lay siege to Harlequins' line.
But the visitors' non-stop tackling saved the day and made them the first team to beat the illustrious Stade in Paris in the group stages of the tournament.
Harlequins rugby director Dean Richards:
"It is right up there as one of the best results in my time at Quins.
"It is not just the defence we had but also the discipline. We could have given away penalty after penalty but we didn't. A lot of the boys grew up here.
"We most probably would have lost this game last year. It's a hugely important game and we played outstandingly well.
"We have a huge amount of talent, and there are young boys out there. They are growing up quickly and will learn from matches like this.
"The boys stood their ground and didn't give an inch, and we will have to do exactly the same next week. This is one game of two. Next week is equally as important as this.
"The importance of this game isn't the 76,000 people and the circus around it.
"It's about doing the same thing next week. We have to back it up with a win at the Stoop and by getting through the group.
"But they will come back, they will feel wounded and will have all their guns blazing."
Harlequins skipper Will Skinner:
"We didn't win a game in the Heineken Cup last year but we gained a lot of experience.
"We learned a lot and we are now winning these games when they are close at the end. People will have to start noticing us with the performances we are putting in."
Stade coach Fabrice Landreau:
"We lacked the intensity to win this match and we dropped too many balls.
"It's really disappointing to lose but we will try to find the answers and get back into the tournament. It will be complicated now but we must keep our heads up."
Stade Francais: Camara; Arias, Bastareaud, Liebenberg, Saubade; Hernandez, Oelschig; Roncero, Szarzewski, Marconnet, Marchois, Taylor, Leguizamon, Rabadan, Parisse.
Replacements: Bousses for Arias (71), Gasnier for Saubade (19), Albouy for Oelschig (71), Blin for Szarzewski (56), M. Bergamasco for Taylor (56).
Not Used: Montanella, Vigouroux.
Harlequins: Brown; T Williams, Tiesi, Turner-Hall, Monye; N Evans, Care; Jones, Fuga, Ross, Percival, J Evans, Robshaw, Skinner, Easter.
Replacements: Robson for Percival (63).
Not Used: Brooker, Lambert, Guest, Poluleuligaga, Masson, Malone.
Sin Bin: Care (38).
Ref: Alan Lewis (Ireland).