Ireland began their World League 3 campaign with an impressive 4-1 victory over South Africa in Valencia.
Nikki Evans scored a hat-trick with Nicola Daly's fine solo effort rounding off the scoring in the fourth quarter.
The tournament doubles up as the main avenue of qualifying for next summer's Olympic Games in Rio.
Ireland's next Pool B game is on Thursday when they face current European champions Germany, with United States and Uruguay also in their group.
There are only three guaranteed places for Rio next summer, but a top six finish would keep Irish hopes alive, as the Continental championships are played out over the next few months.
Ireland, currently ranked 14th in the world, started brightly against their 11th ranked opponents and took the lead after only five minutes when Chloe Watkins through ball found Nikki Evans in the circle, and she managed to lift the ball over the advancing goalkeeper.
South Africa equalised in the tenth minute when a long-range pass was deflected at the top of the circle by Kelly Madsen past Ireland's goalkeeper Emma Gray.
It was from a well-worked penalty corner that Ireland regained the lead in the second quarter.
Cliodhna Sargent turned down the opportunity to shoot and her pass found Evans who turned the ball into the net.
South Africa had the better of the third period but failed to convert from two penalty corners, while Anna O'Flanagan was denied at the other the end when her shot was well saved.
However, Ireland dominated the final fifteen minutes and scored twice to seal a famous win.
It was another cross from Watkins that a sprawling Evans redirected for her hat-trick - but the best was saved for last as Nicola Daly scored a superb solo goal in the 55th minute as she flicked the ball up and hammered a low shot in off the post.
Speaking afterwards, captain Megan Frazer said it was a perfectly executed game-plan that inspired the result.
"What we aimed to do in our team talk, we executed exactly on the pitch and it showed in the second half," she said.
"We had good control and were able to put it on the score sheet. It was fantastic"