Ospreys produced a ferocious defensive display to hold on for a deserved win against last season's Heineken Cup finalists Stade Francais.
HEINEKEN CUP POOL THREE
Ospreys: (10) 13:
Pens: Connor, M Jones.
Stade Francais: (3) 8:
Pens: Martin Hernandez.
Sonny Parker scored the crucial try to give belief to the Welsh side who have so far struggled this season.
The Frenchmen were often rocked back by a swarming defence and were limited to just one late try from Lucas Borges.
But a poor kicking display from Juan Martin Hernandez cost Stade dear as the full-back missed four simple chances.
The Ospreys received two early let-offs when Martin Hernandez hit the post with a penalty, then some furious tackling denied flanker Remy Martin a try.
Bodies were being put on the line by the Celtic League champions at the Liberty Stadium, as they repelled waves of Stade Francais attacks.
The pressure being exerted was evident in the number of Welsh players needing running repairs from the physio within the first quarter.
No one was digging deeper than the home forwards, both in the loose and set piece as the much-vaunted Stade Francais line-out found itself losing ball on several occasions.
Martin Hernandez missed another easy penalty kick on the half-hour, but thoughts of points were put aside almost immediately for the injured Andy Lloyd.
Referee Tony Spreadbury attends to the stricken Andy Lloyd
The Ospreys number eight and Stephane Glas suffered a sickening clash of heads as Lloyd tackled the Stade centre.
Referee Tony Spreadbury acted magnificently to swiftly support the head of the unconscious Lloyd, who was stretchered off with his neck in a brace.
Thankfully Glas was able to limp off after a little attention with no serious hurt evident, and Lloyd came to in the dressing room with his neck given the all-clear.
The game resumed with Martin Hernandez finally landing a penalty on target, but the Ospreys hit back immediately.
Centre Parker sailed in under the posts as Connor sold a beautiful dummy in midfield, with the fly-half adding the conversion and then a penalty for a 10-3 lead at half-time.
Martin Hernandez fluffed another simple kick, before a thumping tackle from Ospreys wing Richard Mustoe stopped Julien Arias in the process of scoring.
The Stade wing injured his knee in that collision and must be a doubt for next week's visit by Leicester.
Next it was the Ospreys to go agonisingly close, as skipper Barry Williams had the ball tackled from his grasp as he dived for the line.
Finally the Parisians made the breakthrough their possession deserved, as scrum-half Jerome Fillol sniped down the blind side to send wing Borges over in the right corner.
But Martin Hernandez was again wide with the kick for the extras and replacement Ospreys fly-half Matthew Jones showed the Argentine how it was done with a fine penalty.
The Ospreys lived dangerously in the final 10 minutes, but furiously defended their five-point lead with a mixture of bravery and some fortune.
Ospreys captain Barry Williams:
"We've let ourselves down all season, but we set a bench-mark today that we can't step below again.
"The defence was awesome, the boys did a great job, and luckily enough we held on.
"But we've started something now and we've got to go to Clermont Auvergne next week and probably put in an even better performance to win out there."
Stade Francais coach Fabien Galthie:
"We controlled things in attack but we couldn't score - when you lose the first match in this competition it is always difficult to qualify.
"We had a lot of injuries already and now we've got two more serious ones to contend with in Stephane Glas and Julien Arias.
"We will do our best to play well next weekend, but it is going to be hard. "
Ospreys: Karauna; Mustoe, Parker, L Davies, Williams; Connor, Spice; D Jones, B Williams (capt), A Jones, Newman, Bateman, Thomas, Pugh, Lloyd.
Replacements: M. Jones for Connor (65), James for D. Jones (75), Bennett for B. Williams (75), Millward for A. Jones (65), Cockbain for Bateman (65), Beech for Lloyd (38). Not Used: A. Bishop.
Stade Francais: Martin Hernandez; Borges, Glas, Messina, Arias; Penaud, Fillol; Roncero, Szarzewski, De Villiers (capt), Marchois, M James, Parisse, Martin, Sowerby.
Replacements: Sarramea for Glas (37), Mirco Bergamasco for Arias (49), Rabadan for Sowerby (60). Not Used: Kayser, Montes, Jechoux, Williams.
Referee: Tony Spreadbury (England).