If the final scoreline did not bear witness to the scale of marmalisation, it was because Leinster tired in the final few minutes and conceded tries to Michael Stephenson and Matt Stevens. But the Dubliners put five tries of their own past their hosts, three of them in the opening quarter and four of them works of art. For seven-eighths of the contest they were in a different league in terms of imagination and execution.
Felipe Contepomi, Shane Horgan and the incomparable Brian O'Driscoll were miles too good for the West Countrymen when it came to firing the bullets, loaded with relish by the industrious Keith Gleeson, who single-handedly dismantled Bath at the breakdown.
As a result of all this, Bath let slip a home quarter-final. Had they won the game, it would have been against Leeds; had they fiddled themselves a losing bonus point, it would have been against Munster. Now, they can look forward to a nice little trip to Leicester. They cannot complain, despite having topped their Pool.
Leinster were always likely to have the emotional force with them, for this was win-or-bust. But Bath had plenty of incentive too, and there is no mileage in pretending otherwise.
They ran into Leinster in last season's tournament and lost at the Rec after starting poorly. By comparison, though, their initial efforts a year ago were a minor triumph. Behind after six minutes on this occasion - Guy Easterby moved a penalty in his own 22, Denis Hickie made ground down the left before propelling a kick into midfield and Horgan steamed in from distance - there was worse, far worse, to come. Contepomi scored an interception try from a loose pass by Olly Barkley before O'Driscoll, low-slung and deadly, stepped past a couple of defenders to manufacture a try for Will Green, a Heineken Cup winner with Wasps in 2004.
In the face of all this brilliance, Bath showed nothing outside the scrum, leaving aside the occasional flash of inspiration from Barkley. More worrying still, there was precious little to write home about up front. Lee Mears carried the ball with his customary enthusiasm and there was a bucketload of sweat from Danny Grewcock. But unlike last season, when the Leinster pack often crumbled, Reggie Corrigan and Malcolm O'Kelly handled things quite comfortably, to the extent that it took Bath almost an hour to string together something resembling a concerted attack.
They were rewarded for that effort with a third penalty from Barkley, but - wouldn't you just know it? - Leinster responded with another withering assault from O'Driscoll, who presented Horgan with his second try in the right corner. The Ireland captain then had himself a little dabble down the opposite flank 10 minutes from time and combined sweetly with Jamie Heaslip before claiming the five points as his own.
It was that sort of performance: inventive, dynamic and utterly ruthless in execution. Toulouse lie in wait for the Irishmen. It should be some spectacle.
Bath: Tries Stephenson, Stevens; Conversions Malone 2; Penalties Barkley 3. Leinster: Tries Horgan 2, Contepomi, Green, O'Driscoll; Conversions Contepomi 5.
Bath: M Stephenson; A Higgins, T Cheeseman, S Finau, F Welsh; O Barkley (C Malone, 73), N Walshe (A Williams, 70); D Flatman (D Bell, 40), L Mears, M Stevens, D Grewcock, S Borthwick (capt), A Beattie, M Lipman, G Delve (P Short, 70).
Leinster: G Dempsey (R Kearney, 40); S Horgan, B O'Driscoll (capt), G D'Arcy, D Hickie; F Contepomi (K Lewis, 40), G Easterby; R Corrigan, B Blaney (D Blaney, 79), W Green (E Byrne, 66), B Williams, M O'Kelly (A Byrnes, 79), C Jowitt (E Miller, 35), K Gleeson, J Heaslip.
Referee: N Owens (Wales).