Munster were far from convincing but their 26-10 victory over Castres at Thomond Park on Saturday confirmed them as the first qualifiers for the Heineken Cup quarter-finals.
Johne Murphy's eighth-minute try set the Pool One leaders on their way to a 16-7 half-time lead, with Yannick Caballero hitting back for the French outfit.
Although Castres had nothing but pride to play for, their understrength side ensured a frustrating second half for the home faithful until Wian du Preez touched down with 12 minutes to go.
Unforced errors and missed scoring chances made for a poor display from Munster, who will need to up their game at Northampton in round six as they chase a home draw in the last eight.
Northampton produced a superb second-half fightback to end the Scarlets' quarter-final hopes with a thrilling 29-17 victory at Parc y Scarlets.
The Welsh side needed to win to stay in the hunt for a best runners-up spot and had the better of the first half as a try from wing Vili Iongi plus nine points from first five-eighths Rhys Priestland helped them to a 14-6 interval lead.
But Northampton's renowned forward power changed the complexion of the game after the break as tries from Soane Tonga'uiha and Ben Foden, supplemented by Stephen Myler's 17-point haul, saw them secure a fifth win in a row in all competitions.
In Pool Two, Cardiff Blues marked their 100th match in the competition with a tight 22-15 victory at London Irish to move a giant step closer to the quarter-finals.
Having seen Edinburgh win away to Racing Metro in Paris on Friday night, the Welsh side responded in the perfect manner at the Madejski Stadium.
Sam Warburton's second-half try complemented a fine Leigh Halfpenny kicking display as the Blues look to reach the knock-out stages for the first time since the 2008-09 season.
The result ended London Irish's slim hopes of progress from the pool and ruined head coach Toby Booth's ambitions of marking 10 years at the club with a victory.
Bath's disappointing European campaign continued as they slumped to their fourth defeat in five matches after going down 24-22 against Montpellier in Pool Three following a last-gasp try.
Bath had looked set for victory as two tries from lock Ryan Caldwell helped put them 22-17 ahead going into the final minute, but Montpellier snatched their first Heineken Cup win when Timoci Nagusa went over for a score that was converted by Martin Bustos Moyano.
Matt Banahan also crossed for Bath while Alex Tulou and Pierre Berard scored the hosts' other two tries.
The result leaves Bath bottom of Pool Three on seven points, with Montpellier moving into second spot, level on 10 points with Glasgow but having played a game extra.
Clermont ran in 12 tries to thrash Italian whipping boys Aironi 82-0 in their Pool Four match at Stadio Brianteo to keep alive hopes of a place in the quarter-finals.
The French side raced ahead with some early scores and were already 47-0 in front at the break.
Wingers Sitiveni Sivivatu and Julien Malzieu completed their hat-tricks in the second half, with Brock James kicking seven conversions to add to four from Morgan Parr.
Fullback Lee Byrne scored a brace, while Alexandre Lapandry, James and Elvis Vermeulen also touched down as the French side collected a bonus point ahead of next weekend's home clash with pool leaders Ulster.
A spirited