There were fun and games in the final five minutes and though none of it made a difference to Northampton's win, which was well deserved and consolidated their control of the Heineken Cup's Pool One, it may be revisited when these teams meet again next Sunday.
A pile-up after a scrum – an area of severe Welsh suffering all evening – ended with Dylan Hartley and Gareth Williams brawling and squabbling their way to the sin-bin. Just beforehand, Chris Ashton had dropped Steve Myler's cross kick and blown a third Saints try – but this was greeted by smiles and applause, which told you the way the result was heading.
A good deal of cross border badinage had been traded in midweek – the Blues accused Northampton's tightheads of boring in; Saints responded with dark tales of illegal Welsh wheeling. As words of war go, these were no phonies. The first quarter was replete with scrummaging. Northampton conceded two free-kicks. It was early engaging that inconvenienced them – a temporary problem they soon put right – and not the apparently abrupt departure on Friday of the prop Euan Murray. The Scotland tighthead left having started one of 14 matches this season, due to Test commitments, his religious objection to playing on Sundays and the form of Brian Mujati and Tom Mercey.
The Blues made a good start with Tau Filise and Xavier Rush darting dynamically and they took a fourth-minute lead thanks to Dan Parks. Then there was a sequence of scrums in the Blues 22. With much heaving and steam rising into the night air, four Northampton put-ins and three penalties led to no immediate score, just a knock-on by the flanker Tom Wood. On the Blues' resulting put-in, the visitors were pinged. After two more scrums of Blues discomfort, the first scrum not to end in a free-kick or a penalty ended in the first try. Roger Wilson, the Northampton No 8 was tackled as the packs spun but he slipped a nice ball round the corner to Ryan Powell, who had Paul Diggin roaring up on the left to receive the scoring pass. Myler made it 7-3.
Northampton escaped dodgy defensive positions by nicking three Blues line-outs, through Courtney Lawes and Christian Day. Such was the ebb and flow, with Six Nations bragging rights there to be had among Saints' four England players and Blues' eight members of Wales's autumn squad. The Blues' Scotland fly-half, Dan Parks, kicked penalties after 31, 35 and 37 minutes and his team were 12-7 up. Saints were a man short when, after Lawes dived over a tackle to commit the second of those offences, James Downey went to the sin-bin for halting Tom James's dancing run with a high tackle.
Strangely, considering their set-piece success, Northampton must have felt relief to get three points and parity back just before half-time. The Blues' loosehead, Filise, was shown a yellow card for a hand in a ruck and Myler kicked the penalty. A hundred seconds into the second half hard driving around the fringes took Northampton close to the Blues' posts and Ashton's impatient waving in space on the right was met by passing along the line via Ben Foden. Saints' second try, scored by Ashton, converted by Myler, made it 17-12.
The Blues suffered from theabsence of the injured backs Jamie Roberts, Ben Blair and Leigh Halfpenny. It left Xavier Rush, Tom Shanklin and a couple of others attempting to make headway against the team six points clear in England's Premiership and with three home defeats in almost four years.
The Blues, trailing 20-12 after Myler's 54th-minute penalty, at last won a clean line-out, Gareth Williams finding Sam Warburton at the tail, and the replacement flanker careered a few metres before, almost inevitably, Northampton forced a turnover. Myler was in such a confident groove when he booted his third penalty on 66 minutes that it almost cleared the stand, into the lake behind it. The only remaining question was whether Saints could score two more tries for their first bonus point in this Heineken Cup, after wins over Castres at home and Edinburgh away.
They failed in that, and instead suffered jitters when Lawes went to the sin-bin for killing the ball on 70 minutes. Parks kicked the penalty. But the last-ditch shenanigans scarcely tainted the home side's progress.
Northampton Saints: B Foden; C Ashton, J Clarke, J Downey, P Diggin; S Myler, R Powell (L Dickson, 64); S Tonga'uiha (R Dreyer, 78), D Hartley (capt), B Mujati (T Mercey, 75), C Lawes, C Day, P Dowson (C Clark, 66), R Wilson, T Wood.
Cardiff Blues: C Czekaj; R Mustoe (J Yapp, 43-49), C Laulala, T Shanklin, T James; D Parks, R Rees; G Jenkins, G Williams, T Filise, B Davies, P Tito (capt; M Paterson, 54), M Molitika, X Rush, M Williams (S Warburton, 54).
Referee: R Poite (France)