The men in Black, Green and Gold led 28-12 at the interval at cinch Stadium at Franklin’s Gardens, with scores from Rory Hutchinson, Tommy Freeman and Augustus’ double securing a try bonus point inside the first 40 minutes.
Bath hit back with a try after half-time, but Skosan charged over the whitewash twice more – taking his own Saints tally to seven tries in just five matches so far – to put some gloss on the scoreline and send Northampton into third place in the league table heading into the European break.
The hosts got off to the perfect start, scoring with just one minute on the clock as George Furbank delayed a pass perfectly and Hutchinson exchanged offloads with Freeman to gallop down the right wing and dot down behind the posts.
Both sides were looking to play with the ball in hand, but it was Northampton who notched the next score in the 12th minute with a fabulous team try; Karl Wilkins made the initial break up the right wing, before Saints fizzed the ball back across the pitch for Skosan to offload inside for Freeman to score.
Biggar landed both conversions to make it 14-0, but Bath then enjoyed their first spell of pressure after back-to-back penalties against the hosts, and drove over a lineout maul in the 16th minute with Sam Underhill coming up with the ball.
Danny Cipriani’s conversion attempt was wayward, and Saints then hit back ten minutes later with a broken field, finding space again down the right. Fraser Dingwall was hauled down just before the line, but got the offload away from the deck for Augustus to score – with Biggar nailing his third conversion to extend Northampton’s lead.
Mike Williams then saw yellow for Bath for a high shot on Biggar, and Saints came close to making the extra man count immediately, but Furbank just couldn’t hold on to a loose ball with the line at his mercy after Hutchinson created the space.
But in the 35th minute, Augustus crashed over for his second of the afternoon courtesy of a swift lineout move, after Northampton’s pack won another scrum penalty inside the Bath half and Biggar sent the kick into the corner.
The visitors responded from short range just before the break with Lewis Boyce picking and driving over the whitewash after Saints were penalised twice in quick succession, with Tom De Glanville landing the conversion with the clock in the red to take the scoreline to 28-12 at the break.
Bath reduced the deficit further eight minutes into the second half, once again from close range, as this time Will Stuart scrambled over under the posts after a number of phases inside the 22 – with Sam Matavesi seeing yellow just beforehand as the penalties mounted.
But Saints went straight down the other end and hit back again, with two massive carries from Dingwall creating the space for Skosan to blast through the last defender and score, although Biggar’s conversion attempt was wide of the mark for the first time.
A back-line reshuffle saw Ollie Sleightholme introduced, Biggar withdrawn and Furbank move to fly-half – and after a brilliant counter ruck from Lewis Ludlam, the stand-in No.10 created the sixth try of the afternoon for Saints, and a second for Skosan.
Furbank’s inch-perfect cross-field kick put the score on a plate for the Springbok wing, who gratefully gathered and completed the simple finish, with Furbank also converting with a sweetly-struck kick from out wide to take the scoreline to 40-19.
The five-point win moves Saints up to third in the Gallagher Premiership standings, with two Heineken Champions Cup fixtures in store against Racing 92 and Ulster over the next fortnight.