After batting second in the first two matches and failing to survive past 32 overs as they made 132 and then 169 in reply to big South African scores, skipper Stirling opted to take first dig in the final match.
"The last couple of games haven't been good as a batting group," Balbirnie said. "We wanted to set up a platform. We have done similar to them, with runs on the board."
Stirling and Andy Balbirnie put on 101 for the first wicket in 23.2 overs. Balbirnie was dismissed by Lizaad Williams for a 45 that took 73 balls and included four fours and a six.
Curtis Campher accelerated with 34 off 36 balls before he was bowled by Ottneil Baartman who then bowled Stirling in his next over. The captain had hit three sixes and eight fours in his innings.
Tector was joined by wicketkeeper Lorcan Tucker who hit 26 before he was out with Ireland on 233 and more than seven overs left.
But the innings subsided as wickets began to fall with only Tector able to score freely before he was run out.
Williams, the only South African bowler to get through his full 10 overs, finished with four wickets for 56 runs. while Baartman and Andile Phehlukwayo took two each.
