The National Yacht Club's Finn Lynch took a top-five result in his flight in the opening race of the ILCA 7 European Championships at Andora, Italy.
The race was sailed in a breeze of only three to five knots with a one-knot current running across the course.
Lynch's main rival for Paris 2024, Ewan McMahon of Howth Yacht Club, sailed most of his race in the top ten before slipping to 14th at the finish.
German sailor Philipp Buhl GER won the single race in the ILCA 7 Yellow group, followed by Hungarian brothers Jonatan Vadnai HUN and Benjamin Vadnai HUN.
Reigning Olympic Gold medalist Matthew Wearn AUS won the race in the Blue fleet, followed by Yogev Alcalay ISR and Ondrej Teply CZE.
Jean Baptiste Bernaz FRA won the Red group, with Johan Schubert DEN second and Ethan MCaullay AUS.
191 entries are competing, with the finals scheduled to begin on Wednesday for Gold, Silver and Bronze fleet splits.
"We had very light conditions, shifty and unpredictable with a lot of current that was the key factor today," commented Vasilij Zbogar, the Irish ILCA coach. "Both [Irish sailors] had quite good results though the race was very much on the limit from beginning to end; it was a good day and a good start to the event."
Irish Sailor of the Year Eve McMahon is competing in the women's ILCA 6 Championships but there was no racing despite multiple attempts being made to get races away.
An improved weather forecast is expected for Monday, when both events are expected to sail three races to catch up on the regatta schedule.