Ulster's defence of the Magners League got off to a perfect start at Ravenhill with a three-try 31-16 victory over a Llanelli Scarlets outfit that disintegrated after a positive opening 40 minutes.

David Humphreys topped the score sheet for Mark McCall's side and bagged 21 points from a try, two conversions and four penalties on a night when Ulster trailed the visitors 16-11 at the break after a miserable first-half effort.

Second-half tries from Paul Steinmetz and new signing Mark Bartholomeusz ensured that Llanelli coach Phil Davies' first competitive outing with the Scarlets ended in failure without his charges even managing a point in the second period.

The reigning champions, minus six of their internationals, made a dream start with two scores in quick succession. A Justin Harrison lineout turnover led to Humphreys' opening penalty, after eight minutes, while the Ulster out half was on hand, two minutes later, to get a try after charging down Martyn Thomas's laboured clearance.

But Llanelli, pretty much at full strength and bristling with international experience, refused to be rattled by their error-strewn beginning and with Wales half backs Dwayne Peel and Stephen Jones enjoying the dominance established by their forwards, the Scarlets dominated the rest of the half.

Jones kicked two penalties before hitting an upright with one he should have converted. His error did not stop the Scarlets' charge against a misfiring Ulster and after some swift handling on the right wing channel, Darren Daniel won a kick and chase against Andy Maxwell for the 20th-minute try which gave the visitors the lead.

Jones added the points to make it 13-8 and was on hand again to stretch the Scarlets' lead by another three points after Ulster captain Harrison talked back to referee Andy Ireland and lost his side 10 metres of ground, the Llanelli out half bisecting the posts from 40 metres.

Ulster desperately needed the next score and managed it, four minutes before the break - Humphreys' penalty being Ulster's first points since the 10th minute to make it 16-11 to the Scarlets at half time.

But Ulster came out fired up and determined to make up the lost ground. A penalty from Humphreys saw them begin positively and the double substitution of Kieron Dawson and Matt McCullough helped get Ulster's title defence back on track.

After both Humphreys and Jones missed efforts, the Ulsterman put his side back in the lead 17-16 with his fourth penalty and then, four minutes after the hour, provided a beautiful grubber kick for Steinmetz to make the touchdown.

Humphreys added the two points and then after Jones was wide again, Bartholomeusz collected an interception and ran in from outside his 22. Humphreys duly added the points.