Pool Three/Bristol 0 Cardiff 17:Cardiff Blues clinched top spot in Pool Three and cruised into the quarter-finals by ending Bristol's four-month unbeaten home record on a sodden pitch at the Memorial Stadium.
They will meet the French giants Toulouse in the last eight.
Cardiff went about their business methodically, refusing to be knocked out of their stride by clinging mud and heavy rain.
First-half tries in rapid succession from flanker Maama Molitika and centre Gareth Thomas - both converted by fullback Ben Blair, who also kicked a penalty - kept Bristol at a safe distance.
The home side were never seriously in contention, despite a couple of threatening runs by wing prospect Tom Arscott, as Cardiff joined fellow quarter-finalists Saracens, London Irish, Gloucester, Toulouse, Munster, Perpignan and the Ospreys.
The Blues knew victory would be enough to secure a quarter-final place, and they arrived in the west country buoyed by their New Zealand imports Blair and Xavier Rush agreeing new three-year contracts.
Bristol were without wing David Lemi, who flew home to New Zealand last week because of a family illness, so Anthony Elliott started, while changes up front saw call-ups for prop Alex Clarke and flanker Alfie To'oala.
Elliott was quickly involved in the action, carving through an outside attacking channel and sending fullback Luke Arscott diving over Cardiff's line.
Referee Alain Rolland, though, called play back for an Elliott forward pass, and Bristol's hopes of an early try were dashed.
Some 12 minutes later, Cardiff were denied when centre Tom Shanklin's inside pass to wing Jamie Roberts drifted forward and prevented a 50-metre move being rounded off in style.
Eight minutes later the Wales flanker Martyn Williams dived over in the corner, but the Bristol skipper, Matt Salter, had nudged him into touch and a gripping contest remained scoreless.
Cardiff territorial dominance was finally rewarded with two converted tries in four minutes immediately before half-time.
Molitika claimed the first, powering over in tandem with his backrow colleagues Williams and Rush, Blair adding the extras.
And in first-half stoppage time, Cardiff drove a lineout, and when Bristol struggled to regroup in defence, Thomas crossed at the end of a looping run. Blair again converted and went on to complete the scoring with a second-half penalty. Cardiff's win means Wales have two quarter-finalists for the first time since 2001.
BRISTOL: L Arscott; T Arscott, Higgitt, Brew, Elliott; Strange, O'Riordan; Clarke, Regan, Hobson; Winters, Hohneck; Salter, To'oala, Blowers. Replacements: Cox for Brew (44 mins); Linklater for Regan, Beveridge for O'Riordan, Hill for Strange (all 54 mins); Crompton for Hobson (60 mins); Llewellyn for Hohneck, El Abd for Salter (both 68 mins).
CARDIFF BLUES: Blair; J Roberts, Shanklin, G Thomas, J Robinson; Macleod, Spice; Jenkins, G Williams, Filise; D Jones, Tito; Molitika, M Williams, Rush. Replacements: G Powell for Filise (71 mins); Morgan for Tito (76 mins); Lewis for Rush (78 mins); R Thomas for M Williams (80 mins).
Referee: A Rolland (Ireland).
Last stand insufficient for Stade
Stade Français, twice losing finalists in the European Cup, went out at the pool stage yesterday despite a comprehensive four-try, 31-10 victory at Harlequins. Tries from Dmitri Szarzewski, Julien Arias, David Skrela and Ignacio Corleto ensured a bonus-point win for the Paris side but their hopes were ended by Cardiff's win in Bristol. Harlequins' lone try came from their Irish winger Simon Keogh.
