On resumption, they lost two quick wickets, of set batters Annerie Dercksen (26) and Woolvardt, within the space of three balls, grinding the momentum to a halt, restricting South Africa to 135/8.
For Ireland, medium-pacer Arlene Kelly was the most successful with 3/29 in three overs. Meanwhile, Cara Murray, who dismissed Dercksen and Woolvardt in the 14th over, and Ava Canning claimed two scalps each.
South Africa started the defence well, restricting Ireland to 37/3 in the powerplay. Though Leah Paul (29) and Rebecca Stokell (19) tried to take the attack to their opponents in a last-ditch effort, it proved too little too late as the European team finished at 120 in 17.4 overs.
Seasoned all-rounder Marizanne Kapp was the pick of the South Africa bowlers, claiming four wickets for just 24 runs in her quota of four overs.