Sonians led 14-10 at half-time through Alice King and Aillie Tucker tries, both converted by skipper Nicola Nightingale, in response to a score from Hannah Smith and five points from the boot of Mairi McDonald.
Emma Evans claimed a third try for Sonians and Lana Skeldon converted but the holders fought back through a penalty try for a high tackle by Megan Gaffney, who spent the rest of the game in the sin bin. But the Capital side held on for their first win in the competition and coach Flynn believes it won’t be their last.
“Last year we played the occasion, not the game This time it was all about the game,” he said. “There’s more to come from them.”
Meanwhile, recently-formed Livingston Ladies’ first campaign ended in a showpiece final defeat, as they went down 72-12 against strong pre-match favourites Greenock Wanderers in the women’s National Bowl, with Leanne Moir touching down twice for Livingston.