The Ireland Under-20s, sponsored by PricewaterhouseCoopers, set the tone with a determined first half display as they beat Scotland 15-0 in Inverness.
A Niall Annett try and a penalty try, both in the first half, did the damage for Mike Ruddock's Ireland side as they bounced back from their recent home defeat to France.
The Irish youngsters were quietly confident of turning over Scotland, who had lost their opening two games to France and Wales.
Martin Moore and Michael Kearney returned to bolster the front five, while centre JJ Hanrahan and flanker Shane Buckley made their first starts of the Championship.
Tadhg Furlong, Cathal O'Flaherty, Mark Dolan and Colm O'Shea also gained some valuable experience off the bench, during a hard-fought second period that was slugged out between the packs.
Ireland's greater strength in the scrum and ball-handling ability helped them edge ahead in front of 2,434 spectators.
Moore's scrummaging ability as a promising tighthead helped the Irish eight turn the screw in the scrum and put Scotland on the back foot.
But the Scots had the first sniff of a try when Paddy Jackson's attempted clearance from the 22-metre line was blocked down. Fortunately for the visitors, Scotland knocked on at the crucial moment.
In wet conditions, Ireland exacted some revenge by shoving the Scots back on their own scrum put-in and they clawed the territory back before taking the lead.
The forwards, with Annett, Daniel Qualter and Jordi Murphy leading by example, worked their way through a series of pick and goes on the five-metre line and showed great patience after the Scots had produced two try-saving tackles in the left corner.
The hard work paid off when hooker and captain Annett made use of some space to score from close range, with Jackson failing to convert.
As in Ireland's first two matches, Jackson continued to link well with Blane McIlroy at half-back and there were some strong carries from Michael Sherlock, Andrew Boyle and Tiernan O'Halloran.
Ireland did well to defend a solid maul drive from the Scots, and shortly afterwards O'Halloran led a counter attack that could have led to a second try.
The Irish backs were looking more dangerous on the ball, and another powerful scrum helped set up full-back Sherlock for an eye-catching run.
He broke forward, with support from livewire flanker Aaron Conneely, and although the move broke down, Ireland's dominance in the set piece came to bear again.
Scotland collapsed three scrums close to their try-line and referee Ian Tempest awarded the Irish a penalty try, which Jackson converted.
12-0 in front at half-time, Ireland were back on the defensive for the start of the second half. Scotland centre Harry Leonard failed to convert a penalty from near the touchline. A second miss followed for Leonard.
Jackson, who had missed an earlier effort, showed his worth by landing an excellent penalty goal with ten minutes remaining, moving Ireland into a decisive 15-point lead.
Scotland attacked and attacked thereafter, but Ireland, with fresh legs on the pitch, were able to soak up the pressure and keep their line intact.
Jackson missed a final penalty, but the two-try haul was enough to secure a second Six Nations win for Ruddock's charges.
Referee: Ian Tempest (England)