The Ospreys' qualification hopes in the Heineken Cup hang in the balance following this humbling defeat to Clermont Auvergne.
Julien Malzieu and Napolioni Nalaga grabbed second-half tries for the French outfit in an intense contest at the Stade Marcel Michelin. The crushing result now means the Welsh region must win against Leicester Tigers at the Liberty Stadium next Saturday to stand any chance of reaching the quarter-finals.
Tommy Bowe set the Ospreys on their way with a seventh-minute score, but the French giants dominated proceedings and possession thereafter and eventually the pressure told.
The visitors nearly gained the perfect start when Lee Byrne fed Bowe inside 55 seconds but the Irish wing failed to keep his feet under pressure from Malzieu. However, Bowe made no mistake with a second chance to break the deadlock on seven minutes.
Brock James then kicked Clermont into the lead with three successive penalties, before making it 12-7 with a deft drop goal on the stroke of half-time .
Malzieu struck the killer blow shortly after the hour mark. Byrne failed to deal with James' high up-and-under and Aurelien Rougerie spotted the unmarked wing Malzieu, who galloped home. James notched his fourth penalty before Nalaga sealed victory for Clermont with three minutes remaining.
Scorers -- Clermont: Rougerie, Nalaga tries; James 4 pens, 1 con, 1 dr gl. Ospreys: Bowe try; Biggar con
Clermont Auvergne: Floch (Russell 68), Nalaga, Rougerie, Baikeinuku (Canale 58), J Malzieu, James, Parra, Domingo (Debaty 53), Ledesma, Zirakashvili (Scelzo 66), Cudmore, Privat, Bonnaire, Lapandry, Vermeulen (Audebert 62). Ospreys: Byrne, Bowe, Parker, Bishop, Walker, Biggar, Januarie, James, Hibbard (Bennett 66), A Jones, A Jones, J Thomas, Collins (Tiatia 72), Holah, R Jones.
Referee: D Pearson (RFU)