Needing a victory to go through as one of the two best runners-up, Ospreys coach Lyn Jones opted to use former All Black number eight Filo Tiatia as a midfield battering ram, and the ploy yielded two crucial first-half tries.

And while Tiatia was making huge yards with ball in hand, New Zealand-born centre Sonny Parker, playing at the back of the scrum in the set-pieces, produced a copybook defensive display in the second half to keep the home side out.

The win - the Ospreys' first ever in France - earns them a quarter-final away to Saracens in early April.

Jones took no chances with his selections, with all 15 of the starting line-up having Test experience.

An all-Wales front five was backed up by former All Blacks Marty Holah, Tiatia and Justin Marshall, with James Hook and Gavin Henson given the task of putting the likes of Shane Williams into space.

Bourgoin centre Sebastien Laloo and Hook traded penalty goals, but the visitors could not turn possession into points until Hook levelled the scores on the 20-minute mark after Laloo had again put his side ahead.

Tiatia flirted with a yellow card by going too high in a tackle, but made immediate amends by joining the backline and creating the space for Williams to score the game's opening try.

Hook added the extras, and was calling for the kicking tee barely two minutes later as prop Adam Jones and Henson combined to put full-back Lee Byrne over in the corner.

Hook slipped as he attempted the conversion, which missed by a long way, but the Ospreys went into the half-time break with a handy and deserved 18-6 lead.

The Ospreys started the second spell strongly, and English referee Wayne Barnes was not popular among visiting fans when he disallowed a try to Parker because of crossing.

Bourgoin charged down two consecutive clearing kicks from Marshall before they had a try disallowed by the referee.

The home side had better luck five minutes later when they drove the Welsh pack backwards at speed.

Referee Barnes called on the television match official for a ruling and it went in favour of Bourgoin prop Karena Wihongi.

Laloo's conversion attempt was wide, and the Ospreys were clinging to a seven-point lead as the match moved into its final quarter.

Hook coolly slotted a 35-metre penalty goal to ease the nerves, but it needed several crunching tackles from Parker to keep Bourgoin at bay - especially after Byrne was sin-binned for a late shot.

Bourgoin fly-half Morgan Parra narrowed the margin with a penalty goal in the final minutes, but a Henson interception set up replacement back-rower Jonathan Thomas for the match-sealing try.

The home side had the final say of the match when replacement full-back Florian Denos chipped ahead, regathered and scored.

 

Bourgoin: Tries: Tchougong, Denos. Cons: Parra. Pens: Laloo 2, Parra.
Bourgoin: A. Forest, M. Nicolas, Coetzee, Laloo, Coux, Parra, M. Forest, Tchougong, Genevois, Cardinali, Pierre, Wyatt, Frier, Petrilli, Jooste. 
Replacements: Viazzo for Laloo (66), Denos for Coux (57), Sourgens for Cardinali (63), Monzeglio for Wyatt (57), Williams for Petrilli (57).

Ospreys: Tries: S. Williams, Byrne, J. Thomas. Cons: Hook 2. Pens: Hook 3. 
Ospreys: Byrne, Walker, Parker, Henson, S. Williams, Hook, Marshall, D. Jones, Bennett, A. Jones, Gough, Wyn-Jones, R. Jones, Holah, Tiatia. 
Replacements: James for D. Jones (72), Evans for Wyn-Jones (74), J. Thomas for Tiatia (66). 
Sin Bin: Byrne (80).

Att: 5,500 
Ref: Wayne Barnes (England).