Ireland secured a hard-fought Test match against South Africa in Cape Town, concluding their WXV Global Series campaign with a historic series victory.
The scoreline saw South Africa ahead at nineteen-all when Parsons crossed for her second try, improving her Test record to twenty-nine tries in forty caps.
Ireland had previously lost their opening WXV match against the United States before bouncing back to defeat Japan and South Africa in subsequent fixtures.
Scott Bemand's side also saw off the former nation in a standalone Test held in Cork earlier this year.
South Africa's hopes for a late comeback were ended when Parsons dotted down for her third try of the match.
Jakkie Cilliers received a yellow card ten minutes from time after making a dangerous tackle on Irish fly-half Dannah O'Brien.
The hosts' efforts to regain control were thwarted as Ireland's hunger for tries was rewarded by Aoibheann Reilly and others in the closing stages.
Erin King captained the Irish team which included Niamh Gallagher, Anna McGann, Aoife Dalton, Robyn O'Connor, Dannah O'Brien, and Neve Jones.