Northampton powered to a convincing win at Franklin's Gardens in the EDF Energy Cup after Bristol new boy Mathew Turner had given the visitors the perfect start.

Turner, a South African Under-20 international who qualifies for England through an English mother, crossed twice on his debut to put Bristol ahead 10-5 midway through the first half.

But the home side went on to score 22 unanswered points after taking advantage when Bristol had Robert Sidoli and Kevin Maggs yellow-carded either side of the break.

Referee Nigel Owens brandished five yellow cards - two to Northampton and three to the visitors.

Saints were glad to be back at Franklin's Gardens, where they had not lost in 19 games since March 2007, having suffered defeats at Saracens and Leicester in the previous week.

Director of rugby Jim Mallinder made changes following the late defeat at Welford Road on Wednesday night.

Only three players kept their place and he brought in Nils Mordt and Rob Milligan for their first-team debuts at centre and number eight respectively.

Bristol went into the game desperate for a win. Head coach Richard Hill had seen his side lose their opening five league matches and he named a completely different starting XV following the midweek loss to Saracens.

Hill handed debuts to South Africa Under-20 international winger Mathew Turner - who qualifies for England through an English mother - and fly-half Chris Ashwin. He also included England international hooker Mark Regan in his starting XV.

Bristol got off to the perfect start with a try after just three minutes. Turner did well to gather Lee Robinson's pass and shrug off two challenges to touch down in the left-hand corner. Chris Ashwin missed the conversion.

Northampton were level in the ninth minute. Barry Everitt's long pass found Paul Diggin on the left. He had Sean Lamont outside him, but chose to cut inside and cross for a try that Everitt failed to convert.

Bristol were back in front in the 22nd minute. Vunga Lilo kicked through and Turner beat Lamont to the ball to touch down.

Ashwin's conversion sailed wide and Northampton were in front two minutes later. Lee Dickson capped a sweeping move by gathering Matt Lord's pass to touch down.

Everitt's missed the conversion, meaning the score stayed 10-10, but the Saints fly-half made amends in the 35th minute with a 40-metre free kick that put his side back in front.

He was off-target with another attempt from similar range two minutes later after Bristol lock Sidoli was yellow-carded for holding on.

Bristol were down to 13 men four minutes after the restart after Maggs was yellow-carded for not rolling away as Northampton twisted the knife.

Chris Ashton's try in the 48th minute and Everitt's conversion put the home side 10 points clear at 20-10.

Sidoli then returned for Bristol, but Saints piled on the misery with Chris Mayor crossing and Everitt's conversion made it 27-10.

Bristol were handed a possible way back into the game when Saints' Joe Gray was sin-binned and both sides had a player yellow-carded in the 64th minute.

Northampton's Ben Broster and Mark Irish were yellow-carded.

Lilo grabbed a consolation try for Bristol with nine minutes left and Ashwin converted - before Everitt's penalty with two minutes left completed the scoring.