This was a clinical performance by Northampton, for whom the full-back Ben Foden had a particularly good match, and it lifted the Saints into eighth place in the Premiership.
Some had billed the game as the "battle of the basement", and that is where Northampton, in 10th before the off, had left Bristol by the final whistle. The Saints are now 10 points clear of the Premiership's bottom club, who have only Newcastle, three points above them, for company.
That cushion should be enough to save Saints from any relegation worries, thus guaranteeing that they can afford to extend the capacity at Franklin's Gardens by a further 4,000 from the present 13,500. That was what their owner, Keith Barwell, who was awarded an OBE for services to local government in the New Year Honours, promised the club in his programme address, should relegation be avoided.
This was the last meeting of the season between these two teams and Bristol must be glad to see the back of the Midlanders. This was the fifth time the clubs have met, in the league, EDF Energy Cup and in Europe, and Northampton have been emphatically the superior side, racking up four wins to Bristol's one.
Yesterday's match produced a messy and nervy first half, which was perhaps only to be expected, given the two teams' lowly league positions, but the game was not helped by the frequent sound of Tim Wigglesworth's whistle. Saints sinned more than their opponents in the first quarter, making silly errors such as closing the gap in the line-out before the throw was taken.
The Bristol side featured Dan Ward-Smith, the New Zealand-born No 8 appearing on the ground where, two years ago almost to the day, he suffered a dislocated kneecap and ruptured patella tendon, having subsequently to undergo a knee reconstruction. At the time he had been on the brink of winning a first cap for England in the 2007 Six Nations' Championship. While he made his presence felt here, he did not look quite the force he once was, although he is still willing and able to put his body on the line and in the way of the advancing hordes.
It took a couple of missed penalties by each side in 29-and-a-half minutes of play before the deadlock was broken, Stephen Myler taking advantage of a slip by the Bristol front row, who were penalised for not binding. The Saints fly-half slotted the penalty kick and his side came to life.
The blindside flanker Mark Easter won turnover ball from Robert Sidoli in the home team's half and the ball was passed out to Foden, who is possessed of a wonderful step. He left Bristol's fly-half, Ed Barnes, for dead, sliced through more cover and then found Paul Diggin on his right shoulder. The right-wing cut inside David Lemi and touched down for the first try of the match, to the unadulterated joy of the Franklin's Gardens faithful. It was Diggin's fourth try this season against Bristol, and his fifth altogether.
Myler kicked the conversion, and shortly before the end of the first half he added a second penalty from more than 40 metres. He followed that with another successful kick shortly after the resumption, those three points taking Northampton's points tally against Bristol this season to 150.
Barnes eventually hit back for Bristol, knocking over a simple penalty when Saints infringed at a ruck 10 metres from their own posts, but generally, although they created opportunities, there did not seem to be anyone in a Bristol shirt who was capable of finishing them off.
Bristol also drew howls of anger from the home support when Diggin was taken out while airborne. Diggin survived and was revived, and Saints merely won themselves a scrum. It is likely that the citing officer will want to have a look at the incident again.
There was then a brilliant solo effortfrom Foden, who collected a poor clearance kick and cut diagonally across the Bristol defence before slicing over for a try which was convertedby Myler. When a long miss-pass by the replacement Carlos Spencer put the centre Jon Clarke over the line the result was settled, although Saints suffered the indignity of conceding a last-minute score when Lemi chased up his own kick ahead and touched down for Bristol's solitary try.
Northampton: B Foden; P Diggin (C Mayor, 80), J Clarke, J Downey (C Spencer, 78), S Lamont; S Myler, L Dickson (B Reihana, 80); S Tonga'uhia, D Hartley, E Murray, IFernandez Lobbe (capt; C Day, 78), J Kruger, M Easter, RWilson, S Gray.
Bristol: L Arscott; L Robinson, Neil Brew, L Eves (Nathan Brew, 62), D Lemi; E Barnes, S Perry (capt); M Irish, M Regan (S Linklater, 67), D Crompton (W Thompson, 77), R Winters (M Sambucetti, 62), R Sidoli (M Salter, 72), N Budgett, D Ward-Smith, A To'oala.
Referee: T Wigglesworth (Yorkshire).