Ireland lost their final Super Six match against South Africa, decided on the Duckworth-Lewis method, by 36 runs in a rain-affected contest in Colombo.
The Girls in Green posted 166 with Malahide keeper Mary Waldron top scoring with an unbeaten 33, dominating a last wicket stand of 43 with Ciara Metcalfe (10).
Isobel Joyce (30), Cecelia Joyce (29) and Gaby Lewis (21) all got starts but none were able to kick on against a disiciplined South African attack, for whom Lizelle Lee (2-12), Sune Luus (2-34) and Dane van Niekerk (2-45) all picked up a brace of wickets.
Kim Garth (1-35) dismissed Lee early in the South African innings, but Laura Wolvaardt (32*) and Mignon Du Preez (29*) took their side to 82 for 1 before rain and thunder brought the game to a premature end with the Africans well ahead on Duckworth/Lewis.
After the game Clare Shillington confirmed her retirement from the 50-over format, but stated that she will continue to play T20 cricket.
"It feels like it's the right time to move away from the longer format due to the increased programme and upcoming tour commitments," said Shillington.
"I'm excited to stay involved in the T20 format with a qualifier and World T20 coming around in 2018.
"I'm looking forward to seeing the next crop of players coming through and hopefully I can play some part in their development," added the YMCA batter.
Shillington played 90 times for Ireland in ODI cricket, scoring 1276 runs which included six half centuries.
Perhaps fittingly, Shillington's final match came against South Africa - the team she made her debut against as a 16 year-old back in 1997.
ICC Women's World Cup Qualifier
Ireland: 166 all out (49.5 overs; M Waldron 33*, I Joyce 30, C Joyce 29, G Lewis 21, L Lee 2-12, S Luus 2-34, D van Niekerk 2-45)
South Africa: 82-1 (21 overs, L Wolvaardt 32*, M Du Preez 29*)
South Africa beat Ireland by 36 runs (D/L method)
