Mark Anscombe's charges ran in four tries in all as they continued on their march towards the Heineken Cup quarter-finals. They are now six points clear at the top of Pool 4 with Castres Olympique their chief chasers.

Ulster may have been accused of 'winning ugly' in their past three league victories, but there was no questioning the aesthetic value of this European success.

Four beautifully-crafted team scores - and a pitch-perfect defensive display - blew the Saints away, and left Ulster coasting their 13th straight win of the current campaign.

Ulster's impressive first half performance was all about consistency and concentration in every position on the field, with the two wingmen getting on the scoresheet thanks to intricately-worked interaction between the forwards and the backs.

An early penalty for Saints out-half Ryan Lamb - awarded after Chris Henry had failed to roll away quickly enough - was off target, and a searching kick from Jared Payne, with the full-back chasing his own ball, forced his opposite number Ben Foden to concede a lineout.

Ulster worked the set piece well, and outstanding distribution from the breakdown allowed Paddy Jackson to chip a kick into the left corner where Andrew Trimble outpaced a flat-footed Foden to ground the opening try. Jackson's conversion missed by the narrowest of margins.

Lamb missed a second shot at the posts after 13 minutes - this time a seemingly elementary kick from 32 metres - and his Ulster counterpart Jackson did likewise three minutes later, albeit from a greater distance of 45 metres.

The Northampton number 10 finally steadied his nerves at the beginning of the second quarter, kicking over adeptly from just inside the Ulster half. But that kick counted for little as Jackson nailed a penalty of his own three minutes later.

Lamb's erratic run of kicking form continued as he missed another penalty in the 27th minute, leaving him with a success rate of 25%.

However, some hesitancy from Jackson when faced with a bouncing ball on his own line then gave the hosts a dangerous five-metre scrum. The Ulster scrum proved resilient though as they turned possession over.

A superb Payne clearance into the corner kickstarted another bright spell for the Ulstermen which ultimately led to their second try of the night.

A crafty steal at the bungled Northampton lineout followed and the Ulster backs spread play expertly, allowing Tommy Bowe to eventually touch down by the right hand corner flag courtesy of Paddy Wallace's final pass.

Jackson was again off target with the conversion but the lead was a strong one at 13-3, a deserved 10-point buffer given the quality of the province's play.

Saints closed out the half deep inside the Ulster 22 and ran off at the break with three extra points from their late spurt, Lamb splitting the posts from 13 metres on the stroke of half-time.

Ulster's start to the second period was equally dynamic. Their third try, with 45 minutes gone, was both started and finished by the in-form Payne.

Safely catching the high clearance kick from Lamb, the Kiwi fed Tom Court and continued to make ground, eventually regathering possession from Ruan Pienaar inside the hosts' 22.

Payne, fed by Trimble, dummied the pass to the influential Darren Cave and cut inside to evade Foden once more and finish off a terrific try from the RaboDirect PRO12 leaders.

Jackson converted from a tight angle and although his penalty attempt moments later fell just short of the posts, the lead looked increasingly secure at 20-6.

Centre Cave put in some monster hits and attacked with vigour, clearly relishing the challenge of putting one over on a side that beat Ulster in the quarter-finals two seasons ago.

With Johann Muller exiting at this stage due to a knock on the shoulder, Nick Williams took to the pitch but as the match entered the final quarter, Ulster showed no lack of direction despite the loss of their captain.

They could easily have registered try number four on the hour mark had it not been for a forward pass from Trimble as Wallace surged down the flank.

The Northampton reaction finally came in the 65th minute and Ulster were thankful for Pienaar managing to hold up Jamie Elliott behind the try-line after several minutes of intense pressure from the English forwards.

Finishing the match with 14 men after Iain Henderson's yellow card for illegally slowing down play, Ulster still pushed for the bonus point try in the final 10 minutes.

Their persistence was rewarded when they picked up a loose ball in midfield and lightning quick distribution amongst the backs finally allowed Payne, instrumental in a number of key attacks, to supply lock Dan Tuohy for a simple finish in the right corner.

The lock lurched over to secure Ulster's second point bonus of the tournament, elevating them to 14 points from three matches played and issuing a stark warning to Northampton ahead of Saturday's week return fixture at Ravenhill.

It was a fitting way to crown Ulster's 50th Heineken Cup success and in particular, Cave, Payne and Trimble in the backs and Henderson, Roger Wilson and Henry in the back row will emerge with great credit from their individual performances.