Losing their captain Paul O’Connell to the sin-bin at a vital stage, Munster had to dig deep to see off Northampton Saints on a 12-9 scoreline at Thomond Park. Four penalties from out-half Ronan O’Gara confirmed Munster’s place in the quarter-finals for the 12th successive year.
After a real arm wrestle of a match, four Ronan O’Gara penalties were enough to guided Munster to top spot in Pool 1 and a home quarter-final, but Northampton could still progress with them.
Their hopes of qualifying as one of two best runners-up hinge on what happens on Saturday in games between the Ospreys and Leicester and London Irish against reigning European champions Leinster.
But Northampton’s losing bonus point ended the quarter-final ambitions of teams in other pools like Sale Sharks, Cardiff Blues and the Scarlets.
Tony McGahan’s Munster side, though, have no need to take an interest in the mathematics.
Despite a second half yellow card for their captain Paul O’Connell, and being outmuscled by a dominant Northampton scrum, O’Gara’s place-kicking accuracy proved crucial in the end.
He eclipsed the combined goalkicking efforts of Saints marksmen Bruce Reihana, Shane Geraghty and Stephen Myler, who each landed one penalty.
Northampton had their moments, yet try-hungry backs like Chris Ashton and Ben Foden were largely stopped at source, engulfed by Munster’s red defensive blanket which was typified by the efforts of All Black winger Doug Howlett.
Munster’s man-of-the-match flanker Alan Quinlan also tackled himself to a standstill, and such was the home side’s immense collective effort that Northampton could find no way through even when O’Connell was off the pitch.
Scotland prop Euan Murray and England lock Courtney Lawes, named at blindside flanker, were the only changes for Northampton following their 34-0 drubbing of French champions Perpignan last weekend.
Munster boss McGahan, meanwhile, had hoped to retain the side which accounted for Treviso in bonus point fashion six days ago, but an enforced late change meant winger Ian Dowling starting instead of the injured Denis Hurley (calf).
The initial exchanges were nervous and hurried from both teams, although Munster edged ahead through an O’Gara penalty inside three minutes.
But solid work by the Saints pack, particularly in the lineouts through Juandre Kruger, meant Munster were unable to settle as a tense opening quarter concluded with Northampton relishing the physical combat.
Their appetite was also evident at scrum time, where Murray made life distinctly uncomfortable for Munster loosehead Wian du Preez, and the visitors drew level nine minutes before half-time.
Reihana rifled over a 48-metre penalty that rewarded Northampton’s solid set piece, but the visitors were then pinned inside their own 22 with half-time looming.
A second O’Gara penalty restored Munster’s lead, yet there remained plenty of hope for Northampton that they could emulate Leicester’s achievement of three years ago and win a Heineken Cup tie in Limerick.
Reihana missed a long range penalty chance to tie the score five minutes after the restart, but Saints had another opportunity five minutes later, this time wasted by Geraghty.
Geraghty looked short on confidence and his scuffed kick provided little in the way of a boost. He managed to find his range after 53 minutes, but Munster quickly regained a three-point advantage when O’Gara completed a penalty hat-trick.
It proved the cue though, for Northampton to storm back upfield as skipper Dylan Hartley charged down Munster scrum half Tomas O’Leary’s attempted clearance.
And Munster, who had dropped their intensity up front, panicked slightly under pressure, with O’Connell punished by French referee Romain Poite for hands in the ruck as Northampton attempted to turn the scrummaging screw.
The yellow card decision was a very harsh and not the first of Poite’s to draw the ire of the home crowd. The sin-binned O’Connell could only look on amid escalating Saints pressure, yet Munster incredibly kept their shape – even with Howlett pressed into emergency back row scrum duty and Quinlan in the second row.
O’Gara and Myler then exchanged penalties during the final 10 minutes, but Munster’s superior experience in high-octane European encounters saw them through as the mist descended on a packed-out Thomond Park.