The Republic of Ireland under-21 squad travel to the second leg of their Euro 2027 play-off with a clean sheet and possession advantage following a narrow defeat in Finland.
Finland took control early as Liam Moller raced down the left flank before crossing to Jimi Tauriainen, though Alex Murphy made a crucial save to deny the opener.
Helen later struck the post with another effort while the Irish struggled to contain the Finnish forward pressure.
The breakthrough came in the final minutes of the first half when substitute Helen powered home a header from Moller's pass.
Captain Matias Siltanen nearly added to his team's tally on 43 minutes with a curling strike that missed the target by inches.
Owen Elding, making his under-21 debut, appeared close to scoring but was ruled out for an offside infraction after his headed finish.
Jamie Mullins cleared a rebound from the crossbar while Elding's follow-up effort was disallowed for being out of play.
Substitute Matteo Egan also had a significant opportunity on his debut but blasted wide after receiving a pass from Mullins.
The Republic of Ireland now seek to overturn the deficit in the return fixture.
BBC Sport Northern Ireland reported the match details and confirmed the 1-0 result.
Noah Jauny was active for Finland in the restart, clearing low drives and pushing away headers in the opening five minutes of the second half.
Trent Kone-Doherty introduced himself late in the game with a cross from the left that caused confusion in the Finnish defence.
The Irish side have secured possession to potentially dictate play in the upcoming encounter.
No official statement has been released regarding future match arrangements or squad changes at this time.