South Africa bowler Lonwabo Tsotsobe reacts after a boundary by Stephan Myburgh.
South Africa opener Hashim Amla struck a 22-ball 43 but the rest didn't kick on as they could reach only 145 in the end.
JP Duminy, who scored 84* against New Zealand, made just 12 against the Dutch team.
Netherlands' spinner Ahsan Malik bowled splendidly to take 5 for 19.
Netherlands got off to a pacy start in their run-chase, led by Stephan Myburgh's 51 off 28. But the team fell apart once he was dismissed.
Legspinner Imran Tahir's spell of 4 for 21 helped South Africa survive a Dutch scare while defending 145. SA won by 6 runs in the end.