Tandy’s response to heavy opening defeats against England and France, in which Wales conceded 15 tries and 102 points, was to make four changes.
Uncapped Leicester wing Gabriel Hamer-Webb, Scarlets fly-half Sam Costelow , Dragons second-row Ben Carter and Scarlets flanker Taine Plumtree coming in for Ellis Mee, Dan Edwards, Adam Beard and Olly Cracknell.
Wales made shocking starts in the opening two games but ensured that was not the case on this occasion.
Plumtree and Hamer-Webb both picked up injuries in the opening two minutes. Hamer-Webb was forced off briefly with a bloody nose before Plumtree was permanently replaced by James Botham because of a shoulder problem.
Wales’ discipline was again poor in the opening exchanges with two soft penalties, before Joe Hawkins was sent to the bunker for a high tackle on Scotland flanker Gregor Brown, who had moved from lock to the back row from the victory over England to replace the injured Jamie Ritchie.
Wing Josh Adams made a couple of important early interventions with a crucial tackle on Scotland centre Huw Jones followed by a vital interception.
Wales rallied with 14 men and after a searing break from scrum-half Tomos Williams, the home side produced an identical successful tap penalty move to last week when Carre dived over after the initial drive from Lake.
Hawkins’ card remained yellow as it was deemed a passive tackle but it was still an 11th sin-binning in Tandy’s seven games in charge.
Scotland took advantage of the extra back with a sweeping move that was finished by Steyn.
Hawkins returned and his fellow Scarlets centre Eddie James, along with Lake, Carre and flanker Alex Mann, laid the foundations for Adams to cross for his 24th Wales try.
Costelow, who was starting his first game since July 2025 with Edwards having played the past seven games, converted from the touchline.
Botham was outstanding after his early introduction and a turnover laid the foundations for a Costelow penalty.
Scotland made a couple of early tactical substitutions as prop Pierre Schoeman and back rower Josh Bayliss came on for Nathan McBeth and Max Williamson, with Brown reverting to lock.
After another storming Steyn break, a vital Mann turnover forced a penalty as Wales led 17-5 at half-time, the first time the home side had led under Tandy at the interval.
