The rest of the points came from the boot of Duncan Weir, while replacement Ruaridh Jackson also chipped in with a late conversion.

Despite this round 22 loss, Connacht stay in eighth place in the table which represents their best ever league finish. Eric Elwood's men were ninth last season.

It was the hosts who were first on the scoreboard, out-half Weir thumping over a penalty after the Connacht front row buckled in the scrum. He had missed a long range effort a few minutes earlier.

Yet the sides were level only moments later when Connacht number 10 Miah Nikora stroked a straightforward penalty through the uprights, rewarding his forwards for a good spell of possession in Glasgow territory.

The province began to visibly grow in confidence as the half progressed, the elusive running of centre Henry Fa'afili proving particularly destructive, while the tactical astuteness of Nikora began to take effect.

The out-half's clever cross-field kick released captain Gavin Duffy for a possible scoring opportunity, only for the home rearguard to smother the move.

Before long, the Warriors began to reassert some authority on proceeding and Weir nudged them back in front with a sweetly-struck penalty from all of 50 metres.

The Scots moved further ahead when van der Merwe crossed the whitewash for the game's first try, rounding off a sweeping Warriors move which featured slick interplay from backs and forwards alike. Weir failed with his conversion attempt.

At times the game appeared as though it may boil over, one altercation running for a number of minutes before referee Peter Fitzgibbon restored order.

From the resulting penalty, Weir elected to kick to touch rather than have a shot at goal and the move petered out, bringing a lively first half to a close at 11-3.

Weir stretched the hosts' lead early in the second period with a third successful penalty and they continued to dominate as the game wore on.

The probing runs of Stuart Hogg and Alex Dunbar, aided by yet another sterling performance from young scrum half Henry Pyrgos, kept a frustrated Connacht penned deep in their own territory for long periods.

Somewhat inevitably, it was the home side who altered the scoreboard once more, Weir adding another three-pointer as the Connacht front row coughed up a penalty at a scrum.

The visitors were temporarily reduced to 14 men when replacement scrum half Paul O'Donohoe was ordered to the sin-bin for throwing opposing number Chris Cusiter to the ground off the ball.

From the resulting penalty, Glasgow assumed prime field position and secured a scrum metres from the Connacht line.

The hosts marched the westerners back in the scrum, allowing number 8 Barclay to dot down for a try converted by Weir's replacement Jackson.

As the game drew to a close, Connacht enjoyed their best spell of pressure. But they were unable to convert their territorial advantage into points, and Glasgow's victory means they finish fourth overall and face a daunting trip to the RDS to face Leinster next Saturday.