World record goalscorer, Coetzee, converted a penalty corner drag-flick past Ireland goalkeeper Emma Gray to open the scoring early, but it was to be a game of missed chances for the home team.
On another day Coetzee, who took her world record tally of goals to 231 from 234 Test matches, would have netted a hattrick.
The striker hit the post with her first penalty-corner drag-flick, while the eighth corner saw Gray make a good stick save low to her right.
The half-time watering of the pitch did make life difficult for the players as areas of the surface did not drain efficiently, while the hosts also used a number of corner variations to counteract the sluggish pace of the ball.
The loss of 2011 SA Player of the Year Tarryn Bright in the sixth minute after Coetzee’s PC drag-flick deflected off the post into the centre midfielder’s face, was a big blow to the team’s fluidity.
The team meet Belgium Sunday, and will be looking for a much slicker performance in every department.