Clermont weathered an early storm from the Ospreys to win 27-7 on Saturday and assume a commanding position in the Heineken Cup Pool Three.
Scintillating early breaks from the Ospreys back-line gave the locals cause for concern, not least when Lee Byrne's fabulous angled run handed a try to Tommy Bowe.
But the French shut up shop effectively, starving the Welsh of tidy set-piece ball and piling on the pressure, with Brock James landing three penalties and a drop goal to give his side the advantage in a classic game of Heineken Cup rugby.
Then on the hour mark the Ospreys finally cracked, with the unfortunate Byrne spilling a high ball and Julien Malzieu capitalising on the error to steam home for the game-clinching try.
Clermont still sit third in the pool, but play whipping boys Viadana next week while their main rivals Leicester and the Ospreys will be knocking lumps out of each other in Swansea. They should be able to do enough to clinch the pool - certainly they are in the right form.
Credit to the Ospreys, they stayed in the match - one of those ones where the phrase 'Test match intensity' reared its head more than once in the passing touchline comments - until Malzieu's try. Thereafter it was damage limitation, with even that performed well but rarely did they look like stealing a comeback score.
Instead, as the time ticked away and the Ospreys' efforts became more and more tired, Dan Biggar's long pass was picked off by Napolioni Nalaga for a score that probably was justified in terms of Clermont's overall superiority.
But for a while, that superiority and end result was a distant dream from the goings-on at the Marcel Michelin. Lee Byrne took a fine angle on the Ospreys' first possession and had Tommy Bowe not tripped over his own feet when stretching to take the pass, the Ospreys could have been over the whitewash within 60 seconds.
Four minutes later, Anthony Floch gave watching French coach Marc LiÃ¨vremont a timely reminder of his counter-attacking skills, breaking the Opsreys' line from his own 22 and scorching up to halfway before hoofing the ball ahead. His chase was quick enough, as was Nikki Walker's, but Nalaga was a different speed again, making it first to the ball but just nudging it forward with his hand as he dived for it.
That was a microcosm of the first half, with both sides willing to run and a delightful ebb and flow to it at times. It was the Ospreys who struck first, with an equally delightful try.
Byrne once again took an angle so acute it was almost diagonally back inside, slicing the Clermont defensive line and feeding Bowe with a long pass. There was no stumble this time and Biggar made it 7-0 with the conversion.
The Ospreys were on the front foot and, four minutes later, came within inches of doubling their try count.
Ricky Januarie stole the ball from Nalaga in his own 22 and the scrum-half was set to dive for the try-line only for Seremaia Bai to intervene with superb saving tackle.
This was where Clermont played it clever. With the Ospreys threatening from set-piece ball, Clermont simply gave them none to play with. James kicked down the lines rather than over them, with an effective chase pattern ensuring no counter-attacks. The scrum upped its game and the Welsh found it too hard to cope. With that platform gone, the Welsh were negated.
Brock James reduced the deficit to 7-3 with a routine penalty after Byrne failed to release as a pulsating opening period drew to a close.
Clermont piled on the pressure and, although James' knocked on with the line at his mercy, the Australian fly-half added a second penalty after the Ospreys conceded a penalty in the scrum under their own posts.
The French outfit spurned the chance to take the lead for the first time when James' penalty struck the left-hand upright following Jerry Collins' high tackle on Elvis Vermeulen.
Moments later, Alun Wyn Jones was penalised by English referee Dave Pearson for killing the ball and James made amends to hand Clermont a deserved advantage.
But the Top 14 leaders were not content and James' deft drop goal on the stroke of half-time nudged the home side 12-7 ahead at the interval.
Clermont wasted a golden opportunity to edge further clear in the 48th minute when James pulled his penalty to the right of the posts.
Biggar and James missed penalties before 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 missed the conversion - the third time he struck the posts - and the Ospreys were in deep trouble.
To compound the visitors' misery, Adam Jones was yellow-carded for kicking the ball away and James notched his fourth penalty before Nalaga sealed victory for Clermont with three minutes remaining.
Tries: Malzieu, Nalaga
Pens: James 4
Drop goal: James
For the Ospreys:
Yellow card: Adam Jones (Ospreys, 67, collapsing a maul)
Clermont: 15 Anthony Floch, 14 Napolioni Nalaga, 13 AurÃ©lien Rougerie, 12 SeremaÃ¯a Bai, 11 Julien Malzieu, 10 Brock James, 9 Morgan Parra, 8 Elvis Vermeulen, 7 Alexandre Lapandry, 6 Julien Bonnaire, 5 Thibaut Privat, 4 Jamie Cudmore, 3 Davit Zirakashvili, 2 Mario Ledesma, 1 Thomas Domingo.
Replacements: 16 Willie Wepener, 17 Vincent Debaty, 18 Martin Scelzo, 19 Julien Pierre, 20 Alexandre Audebert, 21 Kevin Senio, 22 Brent Russell, 23 Gonzalo Canale.
Ospreys: 15 Lee Byrne, 14 Tommy Bowe, 13 Sonny Parker, 12 Andrew Bishop, 11 Nikki Walker, 10 Dan Biggar, 9 Ricky Januarie, 8 Ryan Jones (capt), 7 Marty Holah, 6 Jerry Collins, 5 Jonathan Thomas, 4 Alun-Wyn Jones, 3 Adam Jones, 2 Richard Hibbard, 1 Paul James.
Replacements: 16 Huw Bennett, 17 Ryan Bevington, 18 Cai Griffiths, 19 Ian Gough, 20 Filo Tiatia, 21 Jamie Nutbrown, 22 James Hook, 23 Shane Williams.
Referee: David Pearson (England)
Television match official: Brian Stirling (Ireland)