Harlequins reached the Heineken Cup quarter-finals after crushing Connacht on Saturday, while Saracens beat Racing Metro 37-28.
Harlequins sealed a convincing 47-8 win at the Stoop.
The Quins took some time to subdue an enterprising Irish side and were fortunate to lead 6-3 after the first half an hour.
Their set scrum then emphasised their superiority to ensure there was no way back for the Irish who were briefly reduced to 12 men in the second half as they fell to a heavy defeat.
A penalty try got Quins on their way before Tom Williams (2), Ugo Monye - playing his 200th game - George Lowe and Ben Botica all crossed, with Nick Evans landing six kicks.
The Quins' final Pool Three game is at Biarritz next Friday, on which will depend whether they can secure a home tie in the competition when it resumes in April.
Argentinian centre Marcelo Bosch scored two tries as Biarritz recorded a comfortable bonus-point 32-6 win over Zebre.
Centre Benoit Baby and Fijian Seremaia Burotu scored Biarritz's other tries, Dimitri Yachvili converting three of them and also kicking two penalties.
Zebre's points came from two penalties by outside-half Luciano Orquera.
The win leaves Biarritz second in the group on 14 points, 10 behind leaders Harlequins with one game remaining and needing other results to go their way to qualify, with Zebre bottom and pointless.
Owen Farrell kicked a record 10 penalties in a Heineken Cup tie to clinch a sensational 37-28 victory for Saracens at Racing Metro in Pool One.
The England fly-half was imperious with the boot in the face a partisan French crowd with a perfect 11 kicks from as many attempts in a staggering 32-point haul.
Chris Wyles scored Saracens' only try of a tense clash though the Aviva Premiership side had to cope with two yellow cards, a try deficit of three to one and a worrying injury to David Strettle to pull off a vital victory after they had trailed 22-9 after 25 minutes.
The result leaves Saracens one win away from reaching the quarter-finals for the second year in succession.
Clermont Auvergne ran in six tries to secure their place in the knockout stages with a bonus-point 46-3 victory over Exeter.
The French giants led 20-3 at the break thanks to tries from Wesley Fofana and Jean-Marcellin Buttin.
Exeter fought bravely following the restart, but the pressure eventually told and Clermont ruthlessly completed the job with further touchdowns for Damien Chouly, David Skrela, Buttin and Napolioni Nalaga.
The victory, Clermont's 54th in a row at Stade Marcel Michellin, secures their place in the quarter-finals as Pool Five winners and they can ensure a home draw in their final group-stage match against the Scarlets.
Leinster rediscovered their try-scoring touch with a bonus point 33-14 win over the Scarlets which keeps their qualification hopes alive.
The five-try fillip leaves the reigning champions in contention to reach the quarter-finals, ahead of the second part of their rescue mission away to Exeter next Saturday.
The home side had only scored three tries in their four previous pool games, and the loss of Sean O'Brien to illness before kick-off did not bode well.
But first half touchdowns from Cian Healy, Shane Jennings and man-of-the-match Luke Fitzgerald saw Leinster sweep into a 19-6 lead at the RDS.
Scarlets full-back Liam Williams snuck in for a five-pointer before the break, only for his opposite number Rob Kearney to reply with the all-important bonus point score.
Ian Madigan came off the bench to grab a fifth try in the final minute, as the Irish province's focus switches to that decisive clash in Devon where they need another bonus point victory.
Toulon demolished Cardiff Blues 45-25 in Pool Six to march into the knockout stages.
The Blues made a bright start at Stade Felix Mayol and surged into an 8-0 lead thanks to Leigh Halfpenny's early try.
But Toulon fought back and ran riot with seven tries through Rudi Wulf, Xavier Chiocci, Jean-Charles Orioli, Maxi Mermoz, Alexis Palisson, Mathieu Bastareaud and Florian Fresia.
The bonus-point victory sees Toulon restore their five-point lead at the top and while they are already through, they can secure a home quarter-final in next week's trip to Montpellier.
The Blues fought back with tries from Alex Cuthbert, Dafydd Hewitt and Halfpenny but it was a mere consolation.
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