North Belfast athlete Breege Connolly remains the third fastest of Ireland's female qualifiers for the Olympic marathon after Claire McCarthy clocked 2:42.04 in Prague on Sunday.
McCarthy became the latest Irish woman to achieve the standard but only three athletes can represent Ireland in Rio.
Leitrim native Connolly, 38, clocked 2:37.29 at last year's London Marathon.
Maria McCambridge will run the Riga Marathon next weekend in the hope of forcing herself into the Rio reckoning.
Lizzie Lee and Fionnuala McCormack are certain selections after producing times of 2:32.51 and 2:33.15 in Berlin and Chicago last year.
However, the third qualifying spot has remained very much up for grabs over the last year with several athletes attempting to overhaul Connolly's time.
Athletics Ireland are scheduled to confirm their Rio marathon selections on 23 May.
The male selection issue may prove even more contentious with Kevin Seaward (2:14:52), Mick Clohisey (2:15:10) and Sergiu Ciobanu (2:15:17) currently the three fastest qualifiers.
However, Paul Pollock advanced his claims for selection with a superb 14th place at the World Half-Marathon Championship in Cardiff in March when he finished well ahead of his regular training partner Seaward and Ciobanu.
Pollock had planned to run the London Marathon two weeks ago but had to pull out because of a foot injury.