REPORT | WU17 1-0 Portugal
The Cork City ace made the most telling impact at the most crucial time as referee Sofia Gamas pretty much blew the final whistle after that to allow Ireland to extend their celebrations.
Head Coach James Scott made some changes to his line-up following last Monday's 3-1 loss to the same opponent and there was a freshness about their play in the Portuguese heat.
It was the hosts who struck first with a shot from distance rattling the Irish crossbar before Claudia Keenan was called on to make a vital save on 18 minutes.
However, Ireland did produce some neat passages of play - a characteristic of Scott's teams - with Lia O'Leary shooting just wide of the target and also registering a second effort at goal.
Abby Larkin tested the alertness of the Portuguese goalkeeper, Eve Dossen headed wide when meeting a free-kick delivery, and Michaela Lawrence clipped the top of the crossbar with a shot.
While Portugal did have some chances, it was Ireland who looked the most likely to score with Larkin again going close. But luck seemed to be evading them, until Macken changed that for them.
The watch had gone past the 90th minute when Macken got the goal that ends this trip to Portugal on a high and should give Ireland plenty of confidence going into their UEFA Women's Under-17 European Championship qualifiers.
Republic of Ireland: Keenan; Thompson, Dossen (Fleming 68), Macken, O'Hanlon; O'Mahony (O'Brien 80), Lawrence (O'Riley 68); Long (Kelly 56), Loughrey (McCarn 80), O'Leary (Ralph 80); Larkin.
Portugal: Faria; Ramos, Vinhas, Cardoso, Pinto, Francisca; Ferreira, Martins, Joao, Simas, Doce.
Referee: Sofia Gama (Portugal).