Not even the return of Lions number 10 Stephen Jones could inspire the Scarlets as Ulster ended their opening run of Magners League games this season with their third and most impressive victory.

The result has sent Brian McLaughlin's side to the top of the table ahead of the remaining four fixtures in round 5.

Ian Humphreys provided the direction from out-half, landing four conversions and four penalties for a 20-point kicking haul and he also teed up Timoci Nagusa for the Irish province's third try.

Flanker Willie Faloon celebrated his 23rd birthday by scoring his first league try, while Andrew Trimble enjoyed a return to form with a well-taken brace and Ian Whitten rounded off the night with the fifth and final touchdown.

Jones punished Ulster's indiscipline, firing over four first half penalties, and the Scarlets salvaged some pride with two consolation tries from centre Jonathan Davies.

In wet conditions, Ulster fell behind when they dithered when receiving the kick-off from Jones. The Scarlets got on the ball, forced a penalty and Jones kicked them into a third minute lead.

But Ulster responded immediately with one of the best tries of the current league campaign. They won the restart, with Tom Court bursting forward and the ball was quickly swung wide with full-back Clinton Schifcofske getting over the gain-line.

Then stand-in captain Paddy Wallace, whose distribution skills came to the fore, put BJ Botha striding through a defensive gap and the big South African's well-timed pass sent Faloon, who turned 23 on Wednesday, diving over under the posts.

Humphreys converted before the Scarlets managed to build a head of steam with skipper David Lyons marshalling a number of forward drives.

Jones too was inviting his outside backs onto the ball and big winger Sean Lamont caused some problems out wide.

Jones closed the gap to 7-6, firing over his second penalty after Trimble was whistled up for holding onto the ball on the deck.

This pacy game continued to ebb and flow. The excellent Isaac Boss disrupted a Scarlets scrum and scampered towards the visitors' 22, only for a precise tackle from Rhys Priestland to end Ulster's hopes of a breakaway try.

When Scarlets prop Rhys Thomas was sin-binned for a dangerous tackle on Ryan Caldwell, the home crowd sensed that the men in white would press home their numerical advantage.

Humphreys smacked the initial penalty over for a 10-6 scoreline - yet the Welsh region, winners of four of their last five league meetings with Ulster, dug deep and managed to go back in front while down to 14 men.

Ulster were sloppy at restarts and two ruck offences allowed Jones kick a quick-fire brace of penalty goals, moving his side ahead at 12-10.

Their lead lasted until seven minutes before the break. A decent spell of possession near the Scarlets' 22, which saw the industrious Darren Cave and Trimble getting onto the ball on a couple of occasions, ended with Humphreys' second penalty success.

The Ireland 'A' international missed his next attempt at goal but was able to punish Lamont's high tackle on Wallace with a terrific kick from distance in injury-time, giving his side a 16-12 lead to take into second half.

Tightening up their discipline, Ulster nudged further ahead when the Scarlets illegally collapsed a lineout maul and Humphreys mopped up with another well-struck penalty.

Minutes later, Gareth Maule misread a loose kick out of hand from Humphreys and Trimble gobbled it up before racing clear for his first try.

The athletic winger shrugged Maule off the ball, evaded Jones' tackle and cut inside Lamont before using his pace to charge away to the try-line for a fine individual score which went unconverted.

On the hour, Humphreys dinked a lovely kick out to the right touchline for Fijian winger Nagusa to collect and run in Ulster's third try of the night, with the conversion added by the try's creator.

Man-of-the-match Humphreys was back in defensive mode soon after as Ulster let their concentration slip. Martin Roberts, the Scarlets' best player, took a quick tap and his darting run through midfield almost freed up Lee Williams for a try.

Humphreys denied him, getting back just in time to bundle the winger into touch at the corner flag.

The Scarlets had their moments in attack but mostly they were off colour and Ulster had a firm grip on the game. Nigel Davies' men contributed to their own downfall by leaking two intercept tries in the final quarter.

Trimble chalked up the bonus point when he collected a flipped pass from Lamont in midfield and cantered over for Humphreys to convert and make it 38-12.

The Scarlets hit back quickly. After a powerful leg-pumping run from replacement Ken Owens, Roberts and Williams did well to carve out space in midfield and the ball was spread out to the left touchline where centre Davies used his power to shrug off Wallace and dot down for a seven-pointer.

With play getting looser and looser, Ulster replacement Whitten picked off a poor pass from Priestland and romped in under the posts for the hosts' fifth try which Humphreys converted.

A seventh try followed and it went to the Scarlets, with Davies dummying past Schifcofske and scoring to the left of the posts. Jones pulled his conversion attempt away to the right, summing up a forgettable night for the Llanelli-based side.