There was plenty riding on this game for both sides. A bonus point win for Edinburgh would have moved them back into the Magners League's top four with one round to go, while Ulster, winless since January, were hoping to get any sort of result to move themselves above Connacht in the standings.

As it turned out, Ulster had a dream day as they scored four second half tries for a five-point reward at Murrayfield and Connacht, their rivals for Ireland's final Heineken Cup qualification berth, lost heavily to the Scarlets.

The results mean that Ulster have guaranteed Heineken Cup rugby for next season, barring a miracle result for Connacht in Belfast in two weeks' time, and Edinburgh's chances of reaching the league play-offs have significantly diminished.

Despite this reversal, Rob Moffat's men are still mathematically in the hunt to claim the fourth and final spot in the play-offs, with Leinster, the Ospreys and Glasgow Warriors already through.

No side has secured a home semi-final as of yet, so Leinster and Edinburgh will have a huge amount to play when they meet at the RDS in round 18. A bonus point win for Edinburgh in Dublin would catapult them back into the top four, but only if the Cardiff Blues beat Munster - without a bonus point - in their final game.

There are plenty of permutations to mull over heading into what is sure to be a dramatic and exciting final round, for which Edinburgh have to really raise their game.

Speaking afterwards, their coach Moffat said: "Everybody connected with the club is disappointed with way we played today. We're not going to win games if we keep giving away points. We just didn't play well. We kept making mistakes and couldn't build any momentum."

The relief was palpable in the Ulster dressing room as they ended a run of six league games without a win. Indeed, this was their first Magners League victory of the season over a Scottish outfit and first success on Edinburgh soil since February 2006.

A forceful early scrum set the tone for Ulster but they fell behind when Edinburgh fly-half Phil Godman converted a seventh minute penalty.

Ulster had the better of possession during the opening quarter and a swift break from impressive full-back Jamie Smith got them into the hosts' 22 before a knock on ended the move.

In the 12th minute, Ulster edged ahead for the first time. Centre Darren Cave posed the initial threat on the right wing before popping the ball to the supporting Smith who came in on a diagonal run. He crashed over to the right of the posts, after beating Tim Visser's attempted tackle and another from Mark Robertson, and number 10 Niall O'Connor followed up with the conversion.

Godman pushed a penalty wide from the ten-metre line and it was clear that a nervy Edinburgh were struggling when Godman and Nick De Luca, chasing back to cover a long Ulster kick, dithered and almost allowed the onrushing Simon Danielli nip in for the touchdown.

O'Connor landed a well-struck penalty to stretch Ulster's lead to 10-3, but the home side responded strongly to get back on terms for half-time.

They built up a head of steam in the Ulster 22, on the half hour mark, and although Smith did well to halt Ben Cairns' progress, a switch of play out to the left saw big winger Visser power through Ian Whitten's tackle and stretch over the line with O'Connor for company.

Godman added the conversion, which flicked in off the post, and O'Connor missed a penalty from a central position, pushing his effort to the right and wide, before an injury forced him to be replaced.

Edinburgh had a good bit of momentum as the first half came to a close, and Smith did well on two occasions to recover a difficult situation as the Scotts kicked through with intent.

There was little to choose between the sides in the third quarter, but Ian Humphreys, O'Connor's replacement, helped turn the game in Ulster's favour.

Humphreys injected some much-needed pace into a 53rd minute attack, darting through a gap on the right and passing for Danielli to thunder through and get over for the try, with the covering Godman having little chance of stopping his Scotland team-mate. Humphreys' conversion attempt was off target.

Edinburgh, with Lions scrum half Mike Blair on board, rallied well and looked poised to score. De Luca made a slashing run through the middle, but a forward pass to stand-in captain Roddy Grant brough the attack to an abrupt end.

Ulster were let off the hook again, some minutes later, with Godman electing to chip to the corner when Edinburgh, thrusting forward in lightning quick fashion, should have kept the ball in hand.

Back down the other end, Ulster took a 63rd minute opportunity to move 20-10 ahead. Replacement prop Bryan Young was stopped metres out from the line, Ulster quickly recycled and a long pass from Andrew Trimble out to the right was brilliantly turned into a try by centre Whitten.

He gathered a bobbling ball, fended off a first-up tackle from Edinburgh replacement winger Andrew Turnbull and the combined strength of Turnbull and Lions hooker Ross Ford could not stop the strongly-built Whitten from wrestling his way over the whitewash.

Humphreys hit the woodwork in his attempt to add the extras and while a long range penalty from Godman set up a grandstand finish, Edinburgh were badly overrun in the closing stages.

Two converted tries in the space of three minutes saw Ulster pull clear in devastating fashion. First, Humphreys blocked down Cairns' attempted clearance from in front of the Edinburgh posts and the ball bounced up for the Ulsterman to score his side's fourth and most important try of the season.

Humphreys converted his own try and also turned Stephen Ferris' 74th-minute effort into a seven-pointer. A tackle by scrum half Paul Marshall on Godman dislodged the ball and pacy flanker Ferris took full advantage to scoop it up and gallop over from 30 metres out.

With Ulster tiring slightly, Edinburgh showed how dangerous they can be in broken play by running in two late tries, the first of which was scored by Visser for his tenth of the league campaign.

The Dutchman took a pass from flanker Alan MacDonald to finish off after some good work by Blair and De Luca.

Godman missed the conversion but was able to drop-kick the extras for Andrew Turnbull's try, with two minutes to go. Turnbull managed to dance his way over on the left, with Grant and MacDonald both impressive in the build-up.

However, Ulster had the final say as Humphreys punished a Edinburgh ruck offence by firing a last-minute penalty through the posts.