Troy Parrott hailed the "best night of his life" as his first-half brace secured the Republic of Ireland an astounding 2-0 win over the world's fifth-ranked side.
Cristiano Ronaldo's Portugal were expected to come to Dubin and punch their ticket to next year's finals, but instead saw their talisman dismissed as Roberto Martinez's side were humbled at Aviva Stadium.
"I think it's probably the best night I have ever had in my whole life. I have no words to describe it," the AZ Alkmaar striker told RTÉ Sport after receiving his player of the match award.
"I'm overwhelmed. I don't know what words to give. I'm over the moon."
The Boys in Green must now go to Budapest on Sunday and beat Hungary - who beat Armenia 1-0 in Yerevan - to earn a play-off spot, but in the immediate aftermath Parrott could revel in the most famous result on Lansdowne Road since Shane Long downed Germany,
"We all know how important this game was for us, especially given the other result this evening."
His first goal was a header from point blank range after Liam Scales nodded a corner back across goal
"I think that is a part of the game that I have really developed in the last few years - just being in the right areas to score goals," said Parrott, who declared himself to be "buzzing".
His second goal was even more satisfying, getting behind the Portugal defence and cutting inside before beating Diogo Costa with a clever finish at his near post.
"I saw the space open up between his legs. It's always hard for keepers to get back when ball is across his body," he said.
"I feel great, I feel ready. It's such a relief and overwhelming feeling to see the hard work pay off."
