Luther Burrell and Taqele Naiyaravoro both bagged doubles as Saints smashed the Dragons 48-14 at Franklin's Gardens on Saturday afternoon.
Api Ratuniyarawa, James Fish, Alex Mitchell and Ollie Sleightholme were also on the mark as the black, green and gold claimed another big Challenge Cup win against the Welsh side.
Saints had secured a 35-21 success at Rodney Parade in October, and this win at the Gardens was even more comprehensive.
It means Chris Boyd's men have now taken 10 points from three Challenge Cup games as they took another step towards progressing to the knock-out stages.
The Dragons players had arrived late after some bus issues and they stalled early on, losing the ball after the kick-off and presenting Saints with possession, which they used well.
With a penalty coming, Burrell found a way over the line to give the home side the perfect start, but Dan Biggar missed the conversion in the Gardens breeze.
Saints were then hit with an injury blow as George Furbank was forced off after throwing himself into a tackle to stop onrushing Dragons centre Jack Dixon.
Andrew Kellaway was introduced and Saints continued to pour forward, with Tom Wood just unable to gather an overthrown Dragons lineout five metres from the line.
But the early signs were ominous for the Dragons as they were completely under the cosh and after another spell of Saints pressure, Ratuniyarawa stretched to score.
Biggar converted to make it 12 points for Saints after as many minutes, but the Dragons responded well to their second setback, showing ambition as they continually kicked penalties to the corner.
But after huffing and puffing for some time, the Dragons failed to blow the Saints door down, knocking on to allow their hosts to get back in possession.
The game was turning into a really scrappy affair, with both sides struggling to produce any quality with ball in hand.
Naiyaravoro saw yellow six minutes before the break for a no arms tackle, giving Dragons a chance to respond.
But the Welsh region again failed to make the most of the territory and possession, gifting Saints the upper hand once again.
And with 14 men, Saints scored, with hooker Fish making the most of a dominant lineout drive to dot down, just as he had three times against the Dragons in pre-season.
Biggar converted and the lead was 19-0 at the break, but Dragons did respond quickly in the second period as Adam Warren picked up a clever grubber kick to score.
Josh Lewis converted and Naiyaravoro then returned from the sin bin to even up the numbers.
And Saints soon bagged their bonus point as Burrell flew through unopposed under the posts to score his second try.
Biggar converted with ease and Saints were now really rubbing salt in the wounds as Ratuniyarawa offloaded superbly for Naiyaravoro to dive over the line.
Biggar missed that conversion and another one soon after as he failed to add the extras to a fine Mitchell score that was made by some style and steel from Teimana Harrison.
Saints were all over the Dragons, who looked down and out at 36-7 behind with 25 minutes still to play.
It wasn't long before the next score came with Burrell showing a nice touch as he released Naiyaravoro out wide, with the winger performing a forward roll as he scored again.
Biggar was finding kicking conversions in the wind tough and he missed again, but it wasn't going to matter as Saints were simply cruising to victory.
Dragons did manage to get a second score before the end, with flanker Nic Cudd rumbling over from a lineout drive and Lewis converting.
But Saints had the final say as Sleightholme scooted in from out wide to finish with a flourish.
Biggar converted to cheers from the terrace as Saints put the seal on their easy success.
Saints: Furbank (Kellaway 5 (Strachan 66)); Sleightholme, Hutchinson (Davies 66), Burrell, Naiyaravoro; Biggar, Mitchell; Waller (c) (Davis 52), Fish (Marshall 59), Franks (Painter 52); Ratuniyarawa (Ribbans 63), Moon; Gibson, Wood, Harrison (Eadie 54).
Dragons: Amos, Howells, Warren (Williams 73), Dixon, Kirchner; Lewis, Knoyle (Davies 59); Bevington (Jarvis 52), Hibbard (c), Fairbrother (Thomas 59); Nansen (Screech 52), Evans, Keddie (Taylor 46), Cudd, Griffiths (Benjamin 29).
Referee: Thomas Charabas