The Bok Women can take some confidence from their second-half performance, but they will realise that a Test is 80 minutes long and good sides will punish them when they drop their guard.
Despite a few times when they looked good with ball in hand, the Bok Women's discipline unfortunately let them down, while they also made too make mistakes on attack and defence, which handed possession to the Canadians.
Canada opened the scoring in the sixth minute when Daleaka Menin (prop) crashed over for a converted try, but the Bok Women found some rhythm and were rewarded with a penalty goal by Jakkie Cilliers (wing) after 15 minutes to make it 7-3.
However, Canada hit back almost immediately when Fancy Bermudez (wing) scored from a mistake by South Africa from the restart. They scored two more converted tries in the first half - both long-range efforts by Flo Symonds (centre) and Laetitia Royer (flanker) - to take a 26-3 lead into the break.
The Springbok Women started the second half very well and managed to keep possession through some phases before hard-working flanker Sizo Solontsi popped a great offload to Cilliers, who cut in on the angle and raced 40m for a superb try, which she converted to make it 26-10.
However, the joy was short-lived as Canada again scored from a restart mistake, this time with Alysha Corrigan going over in the corner.
The Canadian right wing bagged her second 10 minutes later and with the sideline conversion finding its target, their lead grew to 38-10.
With the personnel changes at the back starting to find their feet - Nadine Roos moved to scrumhalf, Eloise Webb came in at flyhalf, Libbie Janse van Rensburg slotted in at inside centre and Byrhandre Dolf at fullback - there was move fluency on attack.
The reward came after 62 minutes when Dolf went over for a great try from a strong midfield scrum to make it 38-15.
The Bok Women started playing with more composure and eight minutes later Solontsi crashed over from a tap-and-go penalty which resulted in a strong maul to make it 38-20.
Symonds scored her second to take Canada past 40 points and break some of South Africa's momentum, and in a last-ditch effort to play with width, Caroline Crossley (lock) intercepted right at the end to make it 50 for the visitors.
The second Test is next Saturday in Gqeberha.
Scorers:
Springbok Women 20 (3) – Tries: Jakkie Cilliers, Byrhandre Dolf, Sizo Solontsi. Conversion: Cilliers. Penalty goal: Cilliers.
Canada 50 (26) – Tries: Daleaka Menin, Fancy Bermudez, Flo Symonds (2), Laetitia Royer, Alysha Corrigan (2), Caroline Crossley. Conversions: Julia Schell (5).