Jayson Molumby's sublime winner hurtled Ireland halfway towards the next stage of the UEFA U-17 European Championship qualification series.
The Waterford native, who joined Brighton in the summer, played the captain's role to perfection on 22 minutes by striking the solitary goal of the opening first-phase qualifier with a curler into the top corner from the edge of the box.
By winning their first of three games in the pool, Tom Mohan's Boys in Green now have the opportunity of securing a top-two finish and a place in the elite phase tomorrow if they overcome Malta, hammered 5-1 by Sweden in yesterday's other game.
Ireland were much the better side in Tammela, with goalkeeper Mark Travers untested in the second half as the limited hosts struggled to mount a comeback.
Sheffield United's Stephen Mallon, the latest Northern Ireland teen to defect to the Republic, was impressive in attack on his debut and Ireland created a number of chances to kill off the tie.
Late on, substitute Glen McAuley almost added a second but the Liverpool striker's audacious lob from 40 yards veered just wide.
"Getting off to a winning start is massive but that's history now and our focus has to be absolutely on Malta now," said Mohan, hopeful of leading Ireland to a second successive U-17 finals next May.
"It's a good start and needs to be followed up with another performance on Saturday."
IRELAND - M Travers (Shamrock Rovers); C Carroll (Oxford Utd), D Rice (West Ham), J Finnerty (Aston Villa), T Wilson (Manchester City); J Molumby (Brighton), L Browning-Lagerfeldt (IF Brommaopojk), D McKenna (Wolves), L O'Connor (Villa, Waterford); S Mallon (Sheffield Utd); M Cregan (Stevenage). Subs: G McAuley (Liverpool) for Cregan (51), K Flanagan (C Palace) for Browning-Lagerfeldt (72).