A full recheck and recount was ordered in Ireland South after outgoing Sinn Féin MEP Liadh Ní Riada was poised to lose her European seat to Green Party Senator Grace O'Sullivan by a mere 327 votes on the 18th count.
Ms O'Sullivan snatched the fifth and final seat with a vote of 98,706 after a marathon four-day count - a mere 327 votes ahead of her rival, Ms Ní Riada, who garnered 98,379.
Returning officer Martin Harvey said a recheck and recount was formally requested by Ms Ní Riada - and he had agreed to her request.
The recheck will begin at 9am today - with a full recount, if launched, likely to take three or four days.
However, there is still the possibility that if Sinn Féin is happy with the recheck, that the full recount will be called off.
The mere 327-vote margin separated the two candidates out of more than 755,000 votes cast in the sprawling 12-county constituency.
Former GAA president Sean Kelly topped the poll for Fine Gael and was elected on the ninth count.
Former Fianna Fáil minister Billy Kelleher was elected on the 17th count after exceeding the quota, while Wexford Independent TD Mick Wallace (112,441) and Fine Gael's Deirdre Clune (111,012) face being elected without reaching the 119,866 quota.
However, after the 18th count, which was the distribution of Mr Kelleher's 11,786 vote surplus, just 327 votes separated Ms O'Sullivan and Ms Ní Riada, in fifth and six places respectively.
Ms O'Sullivan had been 522 votes ahead of Ms Ní Riada after the 17th count.
The recheck will involve an examination of all vote bundles to determine if there are any anomalies. However, a recount will involve a recounting of all ballots.
Ms O'Sullivan said she understood the reasoning behind the recount, given the tight margin involved.
In a dramatic night, Fine Gael saw Deirdre Clune deliver another miraculous performance on transfers - turning an 18,000 deficit to Ms O'Sullivan and Ms Ní Riada around in the space of just two counts.
By the 17th count, Ms Clune had a lead of just under 1,900 votes over her nearest rival. By the 18th she had stretched her lead to 2,300.
That earlier count, which was the distribution of Fianna Fáil Councillor Malcolm Byrne's 80,000 votes, saw Mr Kelleher elected with a massive transfer of 38,767.
Ms Clune critically outperformed her two rivals, having trailed both by almost 18,000 votes before the 16th count. In 2014, she delivered another transfer miracle by overtaking her running mate, Health Minister Simon Harris, on the 10th count to be elected an MEP.