Andrew Coscoran broke a 40-year-old national record to win at the Meeting Nikaia in Nice on Saturday.
The Balbriggan man ran 3:32.68 in the 1500m to better Ray Flynn's national record of 3:33.50 set in Oslo in 1982.
Coscoran had already gone faster than Flynn this year when running a personal best of 3:33.49 mark at an indoor event in Birmingham this year.