Geoffrey NDungu of Kenya won Monday's Dublin Marathon in a course record of two hours, eight minutes, 32 seconds.
Helalia Johannes won the women's race, breaking the Namibian record with a time of 2:30.33.
A stiff breeze on parts of the course made it tough for elite runners chasing the Olympic qualifying mark of 2:15.00.
Sean Connolly from Tallaght was the leading Irish man on 2:18.51 while Belfast's Joe McAlister finished in a time of 2:24.43.
St Malachy's club man McAlister set his personal best of 2:21.06 in Dublin last year.
The conditions made NDungu's run all the more impressive as he bettered the 2010 time of his compatriot Moses Kibet by 24 seconds.
Dublin's Linda Byrne, competing in her first marathon, qualified for London 2012 after finishing sixth in 2:36.21.
Maria McCambridge's hopes of also achieving the Olympic standard of 2:37 were dashed as she clocked 2:40.24 while North Belfast athlete Gladys Ganiel was third Irish woman over the finishing line in 2:42.43.
County Armagh man Paul Hannon retained the men's wheelchair title ahead of Jim Corbett from Banbridge.