Ethiopia's Alemu Gemechu won the men's race at the Dublin Marathon while Nataliya Lehonkova of Ukraine triumphed in the women's event.
Gemechu clocked 2:14.01 to come in six seconds clear of Francis Ngare (Kenya) with Asefa Bekele (Ethiopia) third.
Lehonkova dominated to win in 2:32.08, over a minute clear of Grace Momanyi (Kenya) while Tesfanesh Denbi (Ethiopia) trailed home in third.
Sean Hehir (2:17.48) and Pauline Curley (2:49.29) were the top Irish runners.
Hehir, who had a quick turnaround from the Berlin Marathon on 27 September, led the field around the first turn but, from there on, the African athletes took control.
"It was a balancing act between absorbing the effort from Berlin, recovering and trying to win the national title," said Hehir.
"I'm very happy with the sub 2:20. That's special and to be national marathon champion that's very special too."
Mourne Runners athlete Laura Graham (2:56.21) was the third Irish woman to finish.