Saints see off Ospreys challenge
Northampton edged closer to the European Champions Cup quarter-finals - and a potential home draw - after grounding Liberty Stadium hosts the Ospreys.
First-half tries by flanker Calum Clark and Wales wing George North - his fifth touchdown in two appearances against the Ospreys this season - underpinned a 20-9 Pool Five success.
Fly-half Stephen Myler converted both scores and kicked two penalties to set up next Saturday's group decider against French challengers Racing Metro at Franklin's Gardens.
Victory over the Parisians will not only guarantee that English champions Saints go marching on, it would also ensure home advantage in the last eight.
The Ospreys, eliminated from European contention following a third defeat in five starts this term, mustered three Dan Biggar penalties and trailed by just a point approaching half-time.
But they were ultimately undone by Northampton's superior organisation and technical edge up-front, with England flanker Tom Wood and number eight Samu Manoa delivering commanding displays.
Even though Northampton only scored three points in the second half it was very much a case of job done, with Racing next up on home soil.
Northampton welcomed back captain Dylan Hartley following completion of a three-week ban imposed after he was sent off against Aviva Premiership opponents Leicester just before Christmas, but his England colleague Courtney Lawes again missed out due to an ankle injury.
The Ospreys, meanwhile, paraded eight Wales internationals, yet they were without ineligible flanker Dan Lydiate following his switch from Racing earlier this season, plus several injured players, including Dan Baker, Joe Bearman, Duncan Jones and Nicky Smith.
Wales boss Warren Gatland and his national coaching team looked on as the Ospreys took an eighth-minute lead through a short-range Biggar penalty, which came after flanker Justin Tipuric made midfield headway.
There was much more at stake for Northampton in terms of making European progress this season, yet the Ospreys had no intention of playing second fiddle as full-back Dan Evans' break stretched the Saints' defence.
Northampton were further hindered by seeing full-back Ben Foden limp off with what appeared to be a knee injury just 11 minutes into the contest - James Wilson replaced him - but they recovered in impressive fashion.
The Saints forwards edged close to Ospreys' line and scrum-half Rhys Webb's attempted clearance was charged down by Wood before the ball squirted away and Clark reacted quickest to touch down.
Myler added the conversion for a 7-3 lead, but the Ospreys responded through a second Biggar penalty that concluded an entertaining opening quarter highlighted by both sides being prepared to back themselves with ball in hand.
The temperature on a freezing evening in Swansea metaphorically went up a degree when Saints centre George Pisi tip-tackled Biggar, but referee Jerome Garces opted for a yellow card after viewing television replays.
Biggar dusted himself down to kick the resulting penalty, which narrowed the Ospreys' deficit to a point, but Northampton were soon back on the offensive and punished another Ospreys error.
This time it was Tipuric who was the culprit, spilling possession near halfway following a tackle by Saints centre Luther Burrell, and North gathered possession before sprinting away to score his sixth try of the European campaign.
Myler's conversion opened up a 17-9 interval advantage and the Ospreys had it all to do against heavyweight opposition that at times had flexed its impressive collective muscle.
Prop Alex Waller went close to claiming a third Saints try early in the second period, but it was ruled out following television match official analysis as Northampton strived to put the game beyond doubt.
It took Northampton 28 minutes of the second period to increase their advantage when Myler kicked a penalty after an attempt immediately beforehand bounced back off the the post and Ospreys drifted offside.
It summed up the Ospreys' day, and although they continued to work tirelessly in all areas, there was no way back into a contest the Saints had long since taken control of.