Glasgow Warriors gave an encouraging account of themselves against Ulster at Ravenhill on the opening night of the RaboDirect PRO12 season, delivering a performance that bristled with purpose and resilience but that was ultimately undermined by a number of avoidable mistakes.

Sean Lineen’s men were always in contention, but gave themselves just too much to do by conceding three relatively soft tries and failing to establish their usual level of consistency at the lineout.

But in the leadership of captain Rob Harley, the energy of Stuart Hogg, the power of Rob Dewey and the all-round crispness of Troy Nathan on debut, there were plenty reasons to be cheerful ahead of Munster coming to town to kick-start the Firhill season with a bang next Friday (9 September, kick-off 7.30pm).

Glasgow made a positive start to the game on an increasingly wet night in Belfast, absorbing some Ulster pressure and silencing the passionate Ravenhill crowd with a well-worked score in the 12th minute.

First the Warriors pressed down the Ulster left, and after a period of patient recycling, the point of attack was switched to the opposite corner, where Nathan burrowed over from close range to grab a try on his first competitive appearance for the club. Duncan Weir couldn't land the conversion, but this was just the emphatic early statement the visitors required.

As was to be expected from a proud outfit like the Ulstermen, they hit back almost instantly, seeking to turn the screw through the power of their scrum and the alertness of the strike runners peppered liberally throughout their back division.

Glasgow were defending well, however, both in their first-up tackling and their awareness around the fringes. There was still a price to pay, though, as Ian Humphreys kicked Ulster's first points of the night with a penalty from out on the left after the Warriors infringed at the breakdown.

Worse was to come almost instantly for Lineen's troops, as a Colin Gregor dive pass in midfield was intercepted by home centre Darren Cave, who was suddenly presented with an acre of empty space to canter into en-route to the line. Humphreys kicked the conversion to put Ulster five points ahead.

The remainder of the first half saw Glasgow having to withstand a fair bit of Northern Irish heat, as the hosts pushed for a second score to put themselves in a commanding position going into the break.

It wasn't all Ulster, though, and with Nathan running and kicking intelligently, Glasgow issued the odd reminder that they were still very much in the game. They drew fresh hope as Weir's penalty brought them back to within two points, but almost immediately they conceded what will have felt like a very avoidable try.

With the Belfast side committing numbers to a breakdown close to the Glasgow line, the Warriors responded in kind but failed to man the short side. Ulster scrum-half Paul Marshall simply danced round to score unimpeded in the right-hand corner.

Right on the stroke of the interval, Weir landed a mammoth penalty from way out on the right hand side to set up an intriguing second period.

HALF-TIME: ULSTER 15-11 GLASGOW WARRIORS

Glasgow resumed with a spring in their step, seeking to stamp their authority over the opening exchanges. Dewey began to look threatening when put through on the crash ball, while Glasgow's kick/chase also took on a more convincing, more productive air.

Lineen's team managed to earn themselves a penalty in front of the posts after a string of forward drives was ended by Ulster killing the ball. Weir knocked the ball between the sticks to narrow the gap to a single point, but Ulster went downfield and won a penalty of their own which the nerveless Humphreys duly converted.

The home stand-off soon had another opportunity from the tee, Glasgow penalised for failing to release the tackled player. The kick was from fully halfway, but Humphreys made no mistake to put Ulster seven points to the good.

With the rain now hammering down on Ravenhill, both sides struggled to make coherent headway during the final quarter, even if there was always the sense that this game might have another twist to take.

Ulster passed up the chance to put themselves even further ahead when, for once, Humphreys couldn't take the points on offer at a left-side penalty.

Home skipper Chris Henry crashed over from the back of a 5m scrum to seal Glasgow’s fate.

Ulster: 15 A D'Arcy; 14 C Gilroy, 13 D Cave, 12 N Spence, 11 I Whitten; 10 I Humphreys, 9 P Marshall; 1 P McAllister, 2 A Kyriacou, 3 J Cronin, 4 L Stevenson, 5 D Tuohy, 6 P Wannenburg, 7 W Faloon, 8 C Henry (capt)

Replacements: 16 N Brady, 17 C Carey, 18 A Macklin, 19 N McComb, 20 R Diack, 21 I Porter, 22 P Jackson, 23 P Nelson

Glasgow Warriors: 15 S Hogg; 14 T Seymour, 13 R Dewey, 12 T Nathan, 11 C Shaw; 10 D Weir, 9 C Gregor; 1 J Welsh, 2 P MacArthur, 3 M Cusack, 4 T Ryder, 5 R Harley (capt), 6 J Eddie, 7 C Fusaro, 8 R Wilson

Replacements: 16 F Gillies, 17 R Grant, 18 E Kalman, 19 N Campbell, 20 R Pitman, 21 H Pyrgos, 22 P Horne, 23 F Aramburu.

Ref: L Hodges (WRU)