With the knockout stages to come next April, Munster made a real statement with a storming second half at stadium:mk during which they added 32 points for an astonishing 51-36 victory over Northampton Saints in Pool 1.
The two-time Heineken Cup champions secured a bonus point thanks in the main to a hat-trick of tries by rising star, Simon Zebo, to top the pool on 25 points.
Clermont booked their place in the last-eight with a hard-fought 19-15 success over Ulster at a packed Stade Marcel Michelin.
The two clubs finished on 20 points in Pool 4, and were also level on five match points each from their head-to-head games. In the end, Clermont topped the pool by virtue of scoring two tries to Ulster's one in those head-to-head contests.
Meanwhile, Leinster wrapped up Pool 3 with a convincing 25-3 win against Montpellier at the RDS. Last season's champions had to make do without their first choice out-half Jonathan Sexton, who was forced out with an ankle injury before kick-off.
The remaining quarter-final qualifiers, as well as the line-up for the last-eight, will be revealed when round 6 concludes on Sunday with the last series of matches in Pool 2 and Pool 5.
The draws for the semi-final pairings of the Heineken Cup and the Amlin Challenge Cup will take place at Cardiff City Stadium on Sunday at 5.25pm approximately.
Both draws will be streamed live on ercrugby.com and broadcast live on Sky Sports and on the Canal Groupe channel, infosports+.