Scotland began a new era under Sione Fukofuka with a narrow victory over Wales in the opening round of the Women's Six Nations.
Front rowers Kelsey Jones and Sisilia Tuipulotu crossed in a promising first half for Wales - whose wait for a championship win now extends to six matches - while Chloe Rollie finished off a sleek move for the visitors.
Shona Campbell and Lucia Scott ran in tries for Scotland after a huge momentum shift in the second half, while Wales captain Kate Williams pulled one back to set up a frantic finale.
Rallied by the Principality Stadium crowd, Wales threw the kitchen sink at Scotland as the clock ran close to 90 minutes, but Scotland held on to beat their Celtic rivals for a fifth successive match.
They will now look ahead to next Saturday, when they host reigning champions England at Murrayfield, while Wales welcome France to Cardiff Arms Park.
Wales looked comfortable in defence in the early stages, with new defence coach Tyrone Holmes clearly having an impact, but were caught narrow for the opening score.
Emma Orr led the counter-attack through the midfield before the ball found its way out wide to Rhona Lloyd, who selflessly passed back inside for Rollie to cross.
Wales hit back almost immediately off line-out ball, Kelsey Jones finding Bethan Lewis before joining the back of the rolling maul and dotting down.
It proved a double blow for Scotland with prop Leah Bartlett sent to the sin bin on her 50th appearance for an infringement in the build-up.
Wales took advantage on 20 minutes, with a Gwen Crabb turnover gifting them a promising attacking platform, and while line-out ball was slightly overthrown, Tuipulotu took a clean catch and bulldozed her way through.
Wales then fluffed a couple of promising attacks as the set-piece wobbled, but overall looked a different side to the one which was outmuscled by Scotland at last summer's World Cup, with teenage debutant Jorja Aiono a willing ball-carrier.
Scotland reduced the deficit to two points with a Nelson penalty and looked the more threatening side towards the break, but they threw away a golden opportunity when Lana Skeldon was penalised for dummying a throw into a five-metre line-out.
