Courtney Duffus made his debut for Republic of Ireland Under-21s on Friday evening.
The powerful forward, 20, was named in the starting line-up alongside Harry Charsley for the Euro Under-21 qualifier against Slovenia.
It was the in-form midfielder Charsley who put Noel King's side ahead on 87 minutes before a 2-0 win was sealed in stoppage time.
The result leaves Ireland fourth in Group 2, with a win over Serbia on Tuesday offering the chance to go second.
In World Cup qualifying action, Bryan Oviedo was an unused substitute as Costa Rica defeated Haiti 1-0.
Cristian Gamboa's goal means Los Ticos lead Group B with their 7 September showdown with Panama determining top spot.
Returning to Under-21 level, Shayne Lavery played 78 minutes for Northern Ireland, but a late goal from Iceland means they remain winless in Euro qualifying Group 3.
And there was also a disappointing result for Wales Under-21 captain Gethin Jones, as his side lost 4-0 to Denmark.
The Welsh now face a crucial two final games which will decide whether they have a place at the finals next summer.