Tries from Soane Tonga'uiha and a stunning 70 metre effort finished by Lee Dickson along with 13 points from the boot of Stephen Myler did the damage as Ulster eventually ran out of ideas having held their own and the half-time lead.

The Saints were off to the best possible start, drilling a maul from their own 22 before Andrew Trimble showed signs of nerves fumbling Myler's deep kick. Saints' scrum was strong and with Dylan Hartley hitting it up just 10 metres out, Tonga'uiha came from nowhere to barrel through Ulster defenders and despite being dragged down short, the big prop span and slammed down to almost lift the roof off.

Myler converted but Ulster would get off the mark quickly after, a strong set piece of their own allowing Ian Humphreys to slot a penalty from just inside halfway.

The Ulstermen took the front foot and stringing the phases together in Saints' 22, Simon Danielli broke free to run over, but with the vital pass narrowly forward the Saints could breathe easy. Not for long though, it needed a trademark Courtney Lawes hit to stop Trimble in full flight and the visitors recycled to present Humphreys with a second kickable chance of the afternoon.

His successful effort made it a one-point ball game and after their quickfire start, the Saints were now looking for some possession and time in Ulster territory.

It eventually came and despite a solid line of white, the Saints got a shot at goal as Ulster failed to roll away. Myler's effort drifted narrowly wide however and Ulster would strike in clinical fashion. Line breaks in midfield had Saints on the back foot and when Trimble cut through off a smart offload from Rory Best, the Irish winger was over for the game's second try.

Pressure remained too from the restart, but the Saints almost scored a rapid breakaway through Ben Foden, who raced after his own punt after Ulster spilled in midfield. Humphreys couldn't handle the bouncing ball but with Foden outnumbered, Ulster scrambled to negate the chance. Nevertheless, play was pulled back for Humphreys' knock on and when the Saints earned a penalty in the subsequent play, Myler clipped over a three pointer to end a thrilling first-half.

After the break the Saints were back on the front foot again, though Pienaar and Humphreys did their best to stem the tide with some accurate kicking from hand. Against his former club however, Roger Wilson was rampaging and had his hands on the ball a couple of times in the move that eventually ended in Myler levelling the scores with another penalty.

The game was struggling to come to life like the first-half but the spark came almost blindingly as Chris Ashton and Ben Foden carved Ulster apart in an outstanding counter attack. The pair exchanged offloads from 22 to 22 and as Ulster struggled to get men back, the pace stayed on the Saints attack for Jon Clarke to put Lee Dickson through, the scrum-half slamming down.

The Ulster response was quick and direct, forwards and backs involved in a move that took them to within touching distance of the Saints line. With a quickly taken penalty they looked to be in but with a spare man outside him Adam D'Arcy dropped the ball and the Saints were off the hook.

Pace was back on the game and as it eventually settled down with a Pienaar knock on, the scrum then did the work that afforded Myler another shot at the sticks as the hour passed. From 45 metres the effort was struck true and straight and the Saints now had a two score lead.

That said, they couldn't afford to rest on their laurels and a powerful maul brought about another longish effort for Myler just four minutes later. Struck well again, this time it didn't quite have the direction but the Saints were keeping the momentum of the game with a crucial ten point buffer, too.

Another superb move was pulled back for a forward pass, unfortunate for the Saints as Myler's tip on had Paul Diggin clean in but with the clock showing just over six minutes to play, Ulster needed something quick. Twice however the Saints had Ulster scrums back-pedalling and the tackles were flying in in open play. Ulster were running some nice lines with some neat offloads to boot, but the Saints had their number and forced the visitors to hold on.

Myler went to touch and the final seconds were eked out by a trademark Saints maul that allowed Dickson to boot into the crowd. The Saints will now be back in Milton Keynes in three weeks time as Perpignan come to town for the semi-final having beaten Toulon yesterday evening.

Timeline:
4mins SAINTS Try Tonga'uiha Con Myler 7-0
6mins ULSTER Pen Humphreys 7-3
14mins ULSTER Pen Humphreys 7-6
32mins ULSTER Try Trimble Con Humphreys 13-7
40mins SANTS Pen Myler 13-10
HALF-TIME SAINTS 10 ULSTER 13
48mins SAINTS Pen Myler 13-13
55mins SAINTS Try Dickson Con Myler 20-13
65mins SAINTS Pen Myler 23-13
69mins SAINTS Miss pen Myler
FULL-TIME SAINTS 23 ULSTER 13