Scotland ended 10 years of hurt against Wales as they kept alive their RBS 6 Nations title hopes at Murrayfield.
Wings Tommy Seymour and Tim Visser scored second-half tries, while 19 points from fly-half Finn Russell saw Scotland home 29-13 as they posted a first victory over Wales since 2007.
Wales' hopes of a 10th successive win in the fixture were thwarted, despite them building a seven-point lead approaching the interval through wing Liam Williams' try, plus two Leigh Halfpenny penalties and a conversion.
But Wales, their hopes of Six Nations silverware in ruins following two defeats on the bounce, could not capitalise after showing early promise as they failed to muster a single point in the second half.
Buoyant Scotland will now head to Twickenham in pursuit of a first Triple Crown for 27 years when they face England on March 11, having beaten Wales by a biggest margin since 1993.
It was a high-class second 40 minutes by the Scots, who as well as keeping Wales scoreless after the break collected 20 points themselves as they thoroughly deserved a victory that backed up their impressive triumph against Ireland earlier this month.
For Wales, it is back to the drawing board, but life is not about to get any easier as their remaining two Six Nations games are against Ireland and France.
Both teams had five points after the first two games of this season's tournament, making this latest meeting between them pivotal in terms of maintaining any title hopes beyond this weekend.
And the early exchanges did not disappoint in terms of attacking intent, with an emphasis placed on trying to exploit space, but watertight defences initially dominated.
Russell kicked Scotland into a fifth-minute lead, but Wales quickly drew level through a Halfpenny strike as he edged closer towards 600 Test points.
Wales appeared marginally quicker in terms of thought and deed, and they illustrated it brilliantly through a superbly-executed try 16 minutes before the break that owed everything to scrum-half Rhys Webb's rapid thinking.
He took a quick penalty 30 metres out from Scotland's line, made headway, then delivered a superb pass to half-back partner Dan Biggar before possession was rapidly shipped wide and Williams crossed for his third try in this season's Six Nations.
Halfpenny effortlessly added the touchline conversion, and Wales almost extended their lead just two minutes later, only for Webb to turn villain on this occasion as he was penalised for pulling back Stuart Hogg during a menacing attack that had Scotland's defence in rapid retreat.
Russell's second successful penalty cut the gap, only for Halfpenny to cancel it out through a 35-metre strike that restored Wales' seven-point advantage approaching the interval.
But Halfpenny then missed a 40-metre penalty chance during the half's closing stages, and Scotland prospered. They established a strong attacking position after clever work by Hogg freed Seymour, and centre Huw Jones was only hauled down five metres from the line before Wales flanker Justin Tipuric won crucial turnover ball.
Wales, though, could not completely clear the danger, and there was enough time for Russell to complete his penalty hat-trick, reducing the visiting side's advantage to four points at the break.
And Scotland continued their resurgence immediately after half-time, rocking Wales back on their heels through a sweeping attack that ended with Visser drifting across from his wing and sending Seymour over with a superbly-timed pass.
Russell added the conversion - his touchline kick went over off the post - and Wales suddenly had it all to do, trailing by three points after being in control for much of the opening period.
Wales centre Jonathan Davies and Scotland scrum-half Ali Price both then made clean breaks as the game began to open up, but it was the hosts that kept the scoreboard ticking when Russell calmly booted another penalty for his fifth successful strike from five attempts.
Wales, with lock Luke Charteris appearing off the bench after recovering from injury, regained some momentum in terms of territory, and Webb was only denied a try by Visser's tackle that forced him marginally over the touchline.
And Visser then sealed the deal for Scotland, sprinting over following a brilliant Hogg pass, and Russell's conversion completed an outstanding second-half display that he sealed with a long-range penalty.