Scotland succeeded where the Lions had failed by beating the tough provincial side at Loftus Versveld, and the victory means their tour of South Africa, which has been disrupted by a welter of injuries, has finally taken off.
Stanger, who is on standby for a call-up to replace the injured Lion wing Ieuan Evans, was the pick of the Scottish backs.
Up front that Scotland ironed out the problems that had beset them in their earlier games and played with purpose, but they also showed subtle touches behind the scrum, and their final of tally of three tries a testament to their inventive play.
The Scots went into an early lead with two penalty goals and a dropped goal from Duncan Hodge. Caspar Steyn replied for Northern Transvaal with two penalty goals.
On the half hour, Scotland made the breakthrough they had threatened. From a set scrum, the Scots moved the ball left, Ron Eriksson and Hugh Gilmour providing the links to send left-wing Craig Joiner on course for an excellent try, which was converted by Hodge.
Two minutes later, Northern responded with scrum-half Chris Breytenbach slipping the fringe defence before collecting his own kick ahead for a try under the posts. Steyn converted and just before half-time his fourth successful kick levelled the scores at 16-16.
Stanger scored his first try early in the second half and again the score came from a scrum. The Scots worked a loop move between Cameron Murray and Hodge before Eriksson and Gilmour sent Stanger racing away for the try line. Hodge converted and then added a penalty goal to provide Scotland with a 26-16 advantage.
Steyn reduced the lead to just four points with another kick, but, in a superb finish by Scotland, Stanger was fed accurately by prop George Graham and crossed for his second try, Hodge converting.
Scott Hastings became the fourth replacement player to join Scotland's injury-hit squad yesterday. The 32-year-old centre replaces Scott Nichol, who became the latest in a line of players to be injured when suffered rib damage in Scotland's game against Gauteng Falcons on Wednesday.
N Transvaal: Tries Breytenbach. Conversions Steyn. Penlties Steyn 5. Scotland: Tries Stanger 2, Joiner. Conversions Hodge 3. Penalties Hodge 3. Drop Goals Hodge.
Northern Transvaal: Bouwer; Esterhuizen, Schutte, van Vuuren, Steyn; de Marigny, Breytenbach; Campher, Tromp, Hurter, Badenhorst, Schroeder, Brooks, Richter, Bekker.
Scotland: Gilmour; Stanger, Murray, Eriksson, Joiner; Hodge, Nicol; Graham, Bulloch, Stewart, Campbell, Grimes, Peters, Hogg, Holmes.
Referee: I Rodgers (Natal).
n Nick Greenstock, the Wasps centre who made his international debut on the recent tour of Argentina, has been named as Will Greenwood's replacement for England's one-off Test against Australia in Sydney on 12 July. Greenwood was ruled out after being concussed playing for the Lions against Free State on Tuesday.