A brutal result for Scotland, far harder to swallow than their loss to France nine days ago.

Bitter, too, as the shortcomings of Glen Jackson, the inexperienced New Zealand referee, were critical at the end. Jackson denied Scotland what looked like a good try, then denied them the chance of one last play at the end of the game. As Vern Cotter and his assistant coaches stormed from their box at the end, it was clear they were not planning a report on Jackson's performance that would be heavy on praise and platitudes.

But then, they will find plenty to concern themselves when they review their own team's performance as well. Scotland lacked precision and composure in the danger zone as they wasted a succession of chances in the Wales 22. Some of their line kicking was poor, while their work under the high ball was alarming. Wales full-back Leigh Halfpenny and fly-half Dan Biggar plucked possession from the air with ease. Getting the ball there is as important as any other phase, and the Scots, quite literally, came up short.

With exception of the final quarter, when they were chasing down a 10-point deficit, Cotter's side lacked intensity over the ball. They might have been fearful of giving up penalties - although they still had a double-digit count against them at the end - but they came off second best at too many collisions. The statistics at the finish suggested they had won almost as many turnovers as their opponents - five against the Welsh six - but there was a powerful impression in the national stadium that Wales won the ones that really mattered.

Wales also dominated the third quarter, which is the one that usually turns out to be critical. In that time, Scotland were pushed back on their heels and they spent much of the period in their own 22. In truth, they were riding their luck as they did not take serious damage on the scoreboard.

It was also a considerable advantage that Jackson, who should have brought the television match official into play more often, checked the big screen after Liam Williams went over in the left corner with 59 minutes on the clock and rightly ruled out the score for an obstruction. Would that he had got a few more critical decisions correct.

Yet as Wales coach Warren Gatland pointed out, these things have a habit of balancing out over time. If the Scots had found a little more composure at critical moments then Jackson's interventions - and non interventions - would have been rendered irrelevant. That quality was missing from fly-half Finn Russell's performance, for the young playmaker was sloppy with some of his kicks and also managed to pick up a yellow card.

That happened when he crashed into his airborne opposite number, Dan Biggar, just after the half-hour mark. Biggar was also the victim of Stuart Hogg's notorious challenge in Cardiff last year, but sympathy for the Welshman evaporated when he was picked up on the referee's microphone saying that the card should be red. Whether he was right or wrong - Wales coach Warren Gatland also thought it was worth a sending-off - it was a monumentally unsporting suggestion, and all too typical of on-pitch exchanges these days.

While Russell was off, Wales exacted punishment by piling on 10 points. A few minutes later, Davies was also sent to the bin - for a high challenge on Johnnie Beattie - but Scotland picked up only three points while the Welsh were a man down. It was just another lesson in how a mature side takes its chances.

It had been clear from the start that Wales had redemption in mind after their flat performance against England the previous weekend. They attacked in waves from the first whistle and there must have been some Scots in the south stand who were watching through gaps in their fingers at that point. But the Scottish defence held firm and all Wales could take was three points from Leigh Halfpenny's sixth minute penalty.

And then the Scots struck back dramatically. Alex Dunbar hammered DAvies in a midfield tackle, Richie Gray moved the ball on to Hogg, and the full-back raced 60 metres to core between the posts, with Greig Laidlaw adding the extras with ease.

Yet Wales kept chipping away. Laidlaw claimed a penalty to take the Scots into double figures, but Halpenny cut the deficit to one point with his second and third penalties. And when Russell departed Wales upped the tempo yet again. Russell's offence had given them three points, but a sizzling counter-attack down the left by Williams, and a crafty blocking run by Davies as he went, created the opening for Rhys Webb to collect Wales' first try.

That took Wales into a 16-10 lead at the break. by then, though, Davies had also been sent for his rest, and Laidlaw clipped over a penalty to cu the deficit to three. Yet Wales were gathering momentum and confidence and there was a whiff of desperation about Scotland's defence.

It was finally breached in the 64th minute. Wales had a position on the right, from where they moved the ball swiftly across the park. The danger was not immediately clear, but Davies ran a superb angle, shook off Matt Scott's attempted tackle and thundered over for their second try.

From then on, though, it was all Scotland. Mark Bennett crossed for what looked like a good try, but Jackson ruled it out for a knock-on - that might not have been - by Sam Hidalgo-Clyne. Eventually, Jon Welsh muscled over for the second try, which Laidlaw converted.

But it was too little and too late. If not quite as late as Jackson seemed to think.