Two days on from his warning, stamping Stewart is off

Northampton 26 Cardiff 15

Northampton were already out of the Heineken Cup at the start of play, and Cardiff followed them at the final whistle, but the pair certainly went with a bang. The Saints' Scotland prop Mattie Stewart was sent off for stamping, and faces missing the Calcutta Cup match against England on 2 February as a result, while Cardiff's lock Craig Quinnell was sent to the sin bin for the second week running. All in a final, fractious few minutes which counted for precisely nothing in the European context.

Stewart's offence, which occurred at a ruck close to the Cardiff goalline as Northampton went for the kill at 23-15 up, was being considered by a disciplinary tribunal last night. A 28-day ban is the recommended punishment, and there is the not inconsiderable rider that it came only 48 hours after Stewart, an Army corporal and former amateur boxer, was severely reprimanded and warned over his future conduct for kneeing and punching in a recent Premiership match against London Irish.

Quinnell, meanwhile, has a club fine hanging over him after his yellow card for punching against Montferrand a week ago, although yesterday he followed Stewart to the sidelines for more of a technical offence. Perhaps mistaking their visitors for that other lot from Ninian Park, Northampton had printed some stern dos and don'ts for their supporters in the match programme. As ever in rugby, though, the disorderliness – and all its ramifications when the heat of the moment dissipates – was confined to the pitch.

Rudy Joubert, Cardiff's coach, reacted to his side's first failure to reach the knockout stages by criticising Northampton's spoiling tactics. "I never thought we were going to lose," said Joubert, "but we weren't going to be allowed to score tries, the way they killed the ball in the first half."

Joubert admitted, however, that Cardiff might have resorted to catch-up rugby too early after the interval, when the Welsh side trailed only 13-12. And in any case, as far as the neutral observer is concerned, neither side have done enough to suggest they were worthy of a place in the last eight. At least Joubert's Northampton counterpart, Wayne Smith, had a win to warm him. Indeed, Smith has an encouraging record of five victories and only one defeat under his belt since his arrival from New Zealand.

When an explosive start might have been expected by Cardiff, for whom a win might have seen them qualify as winners of the pool, instead Northampton shot out of the blocks with a try after two minutes. Their England wing Ben Cohen had already been close to scoring in the right-hand corner when he popped up on his more familiar left flank to round off a sweeping three-quarter move following a line-out.

From then until half-time there ensued a not particularly edifying spectacle of some decent rucking by Northampton, yet to no great effect, and a peppering of the posts by the respective outside-halves, with Paul Grayson landing two penalty goals for the home side, and Iestyn Harris four for Cardiff. Joubert's complaint that referee Iain Ramage was lenient with the Saints had some merit – it was not until the 73rd minute that Andrew Blowers became the first man into the sin bin. By that stage Northampton had strengthened their position with a penalty try, which was awarded in the 43rd minute, for a high tackle by Craig Morgan as Peter Jorgensen bulleted towards the line in a similar move to Cohen's earlier score.

Grayson's conversion and subsequent penalty sandwiched a fifth penalty by Harris. But the latter, playing his first game of rugby union in the land of his birth – England, that is – was unable to unlock a stubborn Saints defence, and Grayson's dropped goal after the late shenanigans finished Cardiff off.

Northampton: N Beal; C Moir, P Jorgensen (S Webster, 75), J Leslie, B Cohen; P Grayson, J Brooks; T Smith, S Thompson (S Brotherstone, 75), M Stewart, J Phillips, R Hunter, A Rennick (M Soden, h-t; C Budgen, 82), A Blowers, B Pountney (capt).

Cardiff: R Williams; A Sullivan, J Robinson, P Muller (M Allen, 77), C Morgan; I Harris, R Howley; S John (P Rogers, 68), J Humphreys (A Lewis, 68), D Young (capt), C Quinnell, J Tait, R Appleyard (S Sititi, 59), E Lewis, M Williams.

Referee: I Ramage (Scotland).