Clermont marches on as Ospreys falters
The defeat means the Ospreys are eliminated from the Champions Cup and cannot progress to the knockout stages.
England wing Nick Abendanon opened the scoring after 24 minutes. Morgan Parra converted and added two penalties to put the hosts 13-0 up at half-time, before Dan Biggar's late penalty went wide.
Jeff Hassler was held up right on the line for Ospreys and Owen Watkin was denied by Abendanon as luck seemed to desert the Welsh region.
However, Scott Baldwin helped put Ashley Beck over in the corner for a deserved score on 58 minutes, with Dan Biggar converting to bring Ospreys back within six points.
Parra stretched Clermont's lead with a long-range penalty, Greg Laidlaw added another three points from the tee and then Luke McAlister's try finally broke the Ospreys' resistance.
Biggar's match finished early as he left the field with a serious looking shoulder injury.
Tries: Abendanon, McAlister
Pens: Parra 3, Laidlaw
Clermont: 15 Isaia Toeava, 14 Nick Abendanon, 13 Peter Betham, 12 Rémi Lamerat, 11 Remi Grosso, 10 Luke McAlister, 9 Morgan Parra, 8 Fritz Lee, 7 Alexandre Lapandry, 6 Peceli Yato, 5 Sébastien Vahaamahina, 4 Arthur Iturria, 3 Davit Zirakashvili, 2 Benjamin Kayser, 1 Raphael Chaume.
Replacements: 16 Yohan Beheregaray, 17 Etienne Falgoux, 18 Rabah Slimani, 19 Paul Jedrasiak, 20 Damien Chouly, 21 Greig Laidlaw, 22 Noa Nakaitaci, 23 Scott Spedding.
Ospreys: 15 Dan Evans, 14 Hanno Dirksen, 13 Ashley Beck, 12 Owen Watkin, 11 Jeff Hassler, 10 Dan Biggar, 9 Rhys Webb, 8 Rob McCusker, 7 Justin Tipuric, 6 Olly Cracknell, 5 Alun Wyn Jones, 4 Bradley Davies, 3 Dmitri Arhip, 2 Scott Baldwin, 1 Nicky Smith.
Replacements: 16 Scott Otten, 17 Gareth Thomas, 18 Ma’afu Fia, 19 Adam Beard, 20 Will Jones, 21 Thomas Habberfield, 22 Sam Davies, 23 Kieron Fonotia.
Referee: JP Doyle (England)
Assistant referees: Anthony Woodthorpe (England), Simon McConnell (England)
TMO: Stuart Terheege (England)