Northampton’s unbeaten start to the season came to a shuddering halt as they were blown away 46-12 by impressive Bristol at Ashton Gate.

Saints lost Edoardo Todaro to a first-minute red card and it was downhill all the way after that as Bristol ran in six tries.

Scrum-half Kieran Marmion scored two and Tom Jordan, Kalaveti Ravouvou, Aidan Boshoff and Luka Ivanishvili also crossed, with Sam Worsley kicking five conversions and two penalties.

JJ van der Mescht and Tom Litchfield scored Northampton’s tries, one of which Fin Smith converted.

Saints made a disastrous start by losing newly-capped Italy wing Todaro to an immediate red card.

Todaro’s dangerous challenge on Worsley while he was in the air left the referee with little alternative and Bristol soon capitalised when Marmion quickly took a tap penalty to dart over.

Bristol soon scored another when Jordan ran a clever angle to collect a pass from James Williams for an easy run-in before they produced the try of the game by bemusing the opposition with some splendid inter-passing.

It culminated in Harry Thacker bursting down the right touchline and, when the hooker was brought down, Marmion was on hand to pick up and score his second.

Bears suffered a blow when wing Jack Bates left the field with an injury to be replaced by Louis Rees-Zammit.

But it did not slow the hosts’ momentum as a thumping tackle by Benhard Janse van Rensburg on Smith saw Ravouvou seize possession before running 45 metres to score.

Northampton’s miserable first half was complete when they conceded a fifth try from replacement Boshoff, who collected a well-timed pass from Worsley to leave Bristol with a 35-0 interval lead.

Six minutes after the restart, Saints at last struck a blow when giant lock Van der Mescht forced his way over to reward their first period of pressure, but Worsley soon extended the home side’s lead with a straightforward penalty.

Saints, a more competitive side in the second half, scored a second from Litchfield after the centre won the race to collect a well-judged kick from George Furbank.

Worsley added a second penalty for a match tally of 16 points before Ivanishvili finished off a driving line-out to emphasise Bristol’s superiority.