VIDEO: WU19s end Portugal tour on a high note
Keeva Keenan scored the decisive goal on 58 minutes to ensure Dave Connell's team followed up last Tuesday's 1-1 draw with another positive performance.
Portugal proved to be a strong opponent over the two games and they showed how dangerous they can be when rattling the Irish crossbar with a free-kick early on.
Connell's side, however, are not easily scared and they were able to turn the momentum around in the favour. The pace of Dearbhaile Beirne, the tricky of Roma McLaughlin, and the slick passing of Megan Lynch allowed them to open up spaces all over the pitch.
Support was never hard to find for Ireland with Lucy McCartan and Niamh Prior providing outlets out wide, while the industry of Evelyn Daly and Hayley Nolan in the middle of the pitch had the Portuguese stretched at key moments.
After a scoreless first half Ireland made some changes but it was Keenan, wearing the captain's armband, who got the opening goal. Unmarked at a corner kick, the Shelbourne Ladies defender perfectly cushioned a header into the back of the net.
Ireland maintained that lead through to the end as they overcame the searing heat and a tricky Portuguese side to claim a morale-boosting win that gives them confidence ahead of the UEFA European Championship Elite Phase qualifiers in April.
Republic of Ireland: Dunne; McCartan, Keenan, Moloney, Prior; Daly, Lynch, H Nolan; Beirne, McLaughlin, McGlynn.
Watch full highlights of the game below: