Northampton head coach Jim Mallinder praised his side for a professional performance in difficult conditions as they took a giant stride towards the LV= Cup semi-finals.
Saints, the Pool Four leaders, scored five tries through wing Fa'atoina Autagavaia, a penalty try, hooker Mike Haywood, prop Gareth Denman and back row Gerrit-Jan Van Vetize plus three conversions and a penalty from fly-half Glenn Dickson for a 34-16 victory that ended Welsh region Newport Gwent Dragons' slim hopes of qualification.
All of the Dragons' points came in the first period as scrum-half Luc Jones grabbed their only try of the match when he scrambled over under a driving maul, while fly-half Jason Tovey kicked the conversion to add to three earlier penalties.
Northampton won the second-half 19-0 as the chaos from torrential rain and a huge hailstorm, which forced the players off the pitch for two minutes, eased after the break.
The match became a forward battle for periods amid the mud which the much stronger English eight, lead by outstanding lock Christian Day, were always going to win.
The only team that can now deny Northampton a place in the Cup semi-finals are Newcastle, who play Saracens on Sunday and the Dragons next weekend, but the Falcons will need to win and score try bonus points in both just to end the group stages level with the Saints.
Mallinder said: "It is looking pretty good. We always enjoy this competition and it is fantastic that we can play our squad players a little bit. They were tough conditions out there so we were pleased to get the win and the bonus point.
"In conditions like that, you can't do anything other than get your set-piece right. You need your pack to do well so they are going to get the line-out and scrummage correct.
"Christian Day did a brilliant job in organising our line-out. All the forwards played well and then you have half-backs who put you in the right position and the backs to run the ball."
Mallinder and his staff did their homework on the Dragons, particularly with their kicking game and forced a number of clearance charge downs.
The Saints boss added: "We talked about putting them under pressure from their kicking game and we did that really well. But a lot of credit to the Dragons as they kept going and, at times, we were stretched.
"This is a good competition and we have a lot of young lads who are waiting for these opportunities to play. These next two weeks are important to us because we then go into a game with Exeter in the league and we have a number of first-team players who will be away on international duty so these younger players need to be match-hardened."
Dragons rugby director Lyn Jones said there were positives to be taken out of the game despite defeat. However, strength in the problematic front row department is a concern.
Jones said: "Our front five had a tough time today. The challenge for me is to see that the expertise comes into the region to advance our ability.
"We totally understand where Northampton are coming from. They are a genuine power side and that is what you are dealing with.
"It is a harsh lesson for us and not nice to take and we need to improve in that department."