Sale paid a heavy price for the sin-binning of Andy Tuilagi – conceding two tries while the Samoa international was off the pitch and slumping to only their second defeat in nine meetings with Northampton at Franklin’s Gardens.
Full-back Ben Foden and Bruce Reihana scored the tries in a decisive three-minute period at the end of the first half, forcing Sale to play catch-up in a scrappy Guinness Premiership encounter.
Foden enjoyed himself against his old club, and lock Courtney Lawes took the chance to pass watching England coach John Wells with a rampaging performance in the loose.
But Northampton fly-half Shane Geraghty failed to stake his claim for promotion to England’s senior squad from the Saxons with an uneven performance in which he was occasionally booed by home fans for kicking away possession.
Sale gave themselves a glimmer of hope when flanker James Gaskell stole over from the blindside of a second-half scrum – but they had to settle for a losing bonus point, sealed by a Charlie Hodgson penalty with the last kick of the match.
Foden’s try brought the game to life at the end of an error-riddled first half in which Geraghty’s early penalty was cancelled out by a long-range effort from Hodgson.
Hodgson and Reihana were off target with further penalty attempts before Tuilagi’s sin-binning, after he tangled with Chris Ashton to give Northampton an important advantage.
They needed no second invitation to exploit it after Sisaro Koyamibole lost possession – allowing Northampton to counter-attack, Geraghty assisting Foden with a long pass.
Ashton was held up short of the line. But Foden arrived in support and drove over for the try which Geraghty converted from an acute angle.
Ashton was denied two minutes later when former England midfielder Ben Cohen, playing his first game at Franklin’s Gardens since he left Northampton two years ago, managed to beat him to a clever kick through from Geraghty.
But Northampton maintained the pressure and stretched their lead with the final play of the half when Reihana broke a weak tackle by Mark Cueto and dotted down.
Geraghty was unable to add the conversion but made no mistake with a well-struck penalty three minutes into the second half.
Sale were quickly back in the game, and Northampton failed to control the scrum near their own line – the ball squirted out and Gaskell scoring a soft try, which Hodgson improved.
Stephen Myler, who replaced Geraghty midway through the second half, pushed a 63rd-minute penalty attempt wide – before Hodgson atoned for a more glaring miss by finding the target after Northampton’s replacement number eight Mark Easter was yellow-carded for killing the ball.
But Sale’s numerical advantage was quickly wiped out when Brent Cockbain joined Easter in the sin-bin for an offence in the loose, and this time Myler added the penalty.
Sale looked like missing out on the bonus point until Northampton went offside under their own post, and this time Hodgson made no mistake.