It was inevitably billed as the first of a brace of Scotland trials, but a South African-born Canadian internationalist stole the show at Scotstoun last night as DTH van der Merwe scored the tries that made the difference.

Those came during a first half in which Glasgow Warriors threatened to rip their local rivals to shreds, scoring three tries in the first 25 minutes, but in the end they were unable to secure either a four-try bonus point or offer any sort of certainty to their supporters in the 6000 crowd that they would once again retain the 1872 Challenge Cup. Strangely, it had been the men from the capital who made the brighter start, Greig Laidlaw setting the tone for his side by charging down an attempted clearance by Peter Horne inside the Glasgow 22.

Moments later, Tim Visser broke a tackle down the left and found support from Greig Tonks only for the full-back to fail to find Ross Ford with what might have been the scoring pass.

However, with Allan Jacobsen having dropped out before the match through illness, constant re-shuffling of their front five in the opening stages, as Ross Ford and Izak van der Westhuizen both suffered injuries, did them no favours. An extraordinary passage of play meanwhile produced the opening score. Ruaridh Jackson was three-quarters of the way through trying to deliver a pass when he realised there was a problem and tried to reel it back in. He dropped it, but then re-gathered and as he did so found the defenders were committed, allowing him to worm his way through and release Murchie who then sent DTH van der Merwe clean away.

A Sean Lamont break down the right, deep into the visitors' 22, then set up the second try as Glasgow worked the ball from the right touchline towards the left where Niko Matawalu popped the ball out of the ruck to feed the unmarked Harley.

Edinburgh were struggling to contain van der Merwe and he then created two more opportunities in quick succession.

The first saw him brush Lee Jones aside only for Matawalu to fail to take the pass that would have let him run in, before he then gave a superb pass out of a tackle to Sean Maitland, who tried to cut back inside Greig Tonks rather than pin his ears back and go for the line.

Nothing was going Edinburgh's way though, and the third Glasgow try inevitably arrived with fewer than 25 minutes on the clock.

Matawalu, who was also causing the opposition all sorts of problems, sent a perfectly weighted box kick towards the left corner where van der Merwe raced onto it.

The way he carried the ball over the line as he slid in meant the referee checked with the replay official before awarding it, but confirmation was duly delivered and Horne converted.

Edinburgh responded by earning the close-range penalty opportunity that let their captain get them off the mark.

A Ladilaw chip down the left touch and a hack on by Tim Visser then applied more pressure to Glasgow, but a promising spell of attacking ended when Piers Francis lobbed the ball weakly towards van der Merwe who claimed an easy mark.

Edinburgh were beginning to have more of the game but their play lacked penetration and another attack was unceremoniously halted when Francis was perfectly legally clattered by Tim Swinson.

As he had at the start of the first half Ladilaw began the second trying desperately to lift his team, and, in a near-identical move to that which saw Henry Pyrgos score against South Africa last month, he received the ball from a lineout, cut clean through the middle of it then lofted the ball towards the Glasgow try line.

He tripped over Maitland's leg as he set off in pursuit, drawing protests from Cox, but they resulted in no more than a penalty against their side for dissent.

Laidlaw did manage to further reduce the deficit with a second penalty and this time his men responded with a superb move which brought them a try.

The initial opening was made by James King's miss-pass, which was taken at pace by Matt Scott who drew defenders to him before releasing Francis, and even van der Merwe's attempt at a covering tackle came too late.

Their side having lost momentum, Glasgow's management started ringing the changes and two penalty strikes from Duncan Weir, their replacement stand-off, either side of another from Laidlaw, eased them towards victory.

They looked set to clinch the bonus point too when Weir rattled down the left touchline before firing a kick towards the goal-line. That set up a four-man race with van der Merwe, Tonks and Laidlaw, but van der Merwe knocked on as he went for his hat-trick.

Glasgow were awarded a penalty at the ensuing five-metre scrum, which Weir sent to touch, and when they were awarded another a traditional festive rammy broke out, but when play resumed it was the home team's turn to infringe at the next scrum and the final chance for the bonus point was gone.