Zebo makes unholy mess of Saints and Munster march on

Some teams might view the dismantling of their scrum as mortally wounding. Munster took it only as the cue to create other areas of merry hell in Milton Keynes. Restarts and the breakdown, to name but two. A rampant performance made a hat-trick of tries for the rookie wing Simon Zebo and a glut of points for Ronan O'Gara.

Munster's five tries helped win Pool One of the Heineken Cup and earn them No 1 seeding for the last eight, with Leinster in second. Ulster will be away to one of them in Limerick or Dublin in early April, emphasising Irish domination juxtaposed with English wreckage. Only the South African-backed Saracens remain standing, assuming they survive a trip to Treviso. A mathematical lifeline for Harlequins is almost certain to be severed today, leaving them to defend the Amlin Challenge Cup. The other five English clubs in the Heineken, including Northampton, are dead and gone.

Munster missed the Heineken quarter-finals last year for the first time in 13 seasons but they were not about to repeat the error. A stunned Northampton director of rugby, Jim Mallinder, had no gripes.

"Munster seemed to up their game from what I've seen in their five previous Heineken Cup matches," said Mallinder. "What they did well was slow us down in the contact area."

Of his dropped England wing, Chris Ashton, who stayed at home after a reported training ground argument in midweek and the announcement of his summer move to Saracens, Mallinder said: "Chris has been in for training the past couple of days. Eitherhe'll get picked by England and he'll be back with us in eight weeks, or he won't and he'll be back next week, fighting for his spot."

A big crowd earned Northampton more than £200,000 but the class was Munster's. Saints led 6-3 after Ryan Lamb hit a post with a penalty then converted his next two before O'Gara – whose late drop-goals had secured wins over Northampton and Castres at the start of this pool – kicked a penalty from 40 metres. The signs of Munster buckling in the scrum began as Saints earned a penalty try after 15 minutes. Dramatic back-pedalling obliged Peter O'Mahony to stick a boot in, and Lamb converted for a morale-boosting seven points.

The Saints lock Samu Manoa made a second rib-rearranger to staunch Donncha O'Callaghan's run but on the flipside Northampton's Calum Clark had all the heavy contact he could handle in attempting to prove he could do a flanker's job for England.

O'Gara's second and third penalties and a drop-goal by Lamb had Northampton 16-9 up before a close-range try for Munster. Phil Dowson, an outside bet for an England place against Scotland on Saturday week, dropped the restart, Zebo and O'Mahony went forward and the former Springbok BJ Botha dived past Manoa.

O'Gara, who will be 35 by the quarter-finals, did not look like missing the conversion or much else and another penalty each for him and Lamb made it 19-19 at half-time. Northampton needed a solid start to the second half; instead another dodgy restart was lost to Zebo, a 21-year-old Ireland Under-20 cap who has come through Munster Schools. He set his side up for a try that was finished at the right corner on a big overlap by Johne Murphy, from passes byO'Gara and Denis Hurley. The sixth kick out of six by O'Gara was the maestro's trickiest and though he would miss a conversion soon after he did not care – Zebo's try, from a lovely pass by Hurley, had Munster 31-19 up.

While Saints had their scrum, they had hope. A second penalty try arrived in the 57th minute; Lamb converted once a scrap had died down, though it cost the scrum-halves, Lee Dickson and Conor Murray, 10 minutes each in the sin-bin.

Manoa hammered Lifeimi Mafi again but the subsequent breakdown brought another penalty for O'Gara: 34-26. An obstruction at the restart let Lamb cut it to 34-29 and the French referee, Romain Poite, kept whistling, this time at a line-out. O'Gara reached 24 points with the penalty and the conversion of Zebo's second try, an interception of James Downey's limp pass on halfway.

Zebo, slashing inside on 76 minutes, completed his hat-trick and with O'Gara off, Ian Keatley converted. Many Saints fans had headed for the M1 before a Scott Armstrong that was no consolation.

Northampton Saints: B Foden; J Elliott (S Armstrong, 69), G Pisi, J Downey, V Artemyev; R Lamb (S Myler, 73) L Dickson (M Roberts, 73); S Tonga'uiha (A Waller, 66), D Hartley (capt), B Mujati (P Doran-Jones, 65), S Manoa, M Sorenson (C Day, 62), C Clark (B Nutley, 62), R Wilson, P Dowson.

Munster: D Hurley; J Murphy, K Earls, L Mafi (D Barnes, 77), S Zebo; R O'Gara (I Keatley, 74), C Murray; W du Preez (M Horan, 55), D Varley (D Fogarty, 74), BJ Botha (S Archer, 73), Donncha O'Callaghan (M O'Driscoll, 73), P O'Connell (capt), D Ryan, J Coughlan, P O'Mahony (Dave O'Callaghan, 73).

Referee: R Poite (France).