After extra-time finished with the score locked at 2-2, Portugal won the penalty shootout as Ruben Neves hit the winning spotkick after Diogo Costa had saved Spain captain Alvaro Morata's effort.
Afterwards, Fernandes declared: "It's always special. Winning for Portugal has a different flavour. Obviously it's been a very difficult season for me at club level, but regardless of that winning for our country, our people, our family is... spectacular.
"Having my parents here, my wife, children, brother, it's always special. We all suffer more here. It's our country, what we miss most when we're away. That's what makes everything special. It's nice to see the bonds we've created.
"We knew that, against both Germany and Spain, when they won the ball back we had to be very quick to react. That was one of the things the coach asked of us. We showed in big moments what we can do. Winning today is the icing on the cake.
"At no point did we think that if we were down we would lose the game. We knew we had the quality to react, to give something more, because we have individuals who, at any moment, can do it."
How can I describe Nuno?!
Fernandes took time to praise PSG wing-back Nuno Mendes, who scored for Portugal on the night.
He continued: "Nuno Mendes today... There are no words to describe that boy! The energy, the strength, the quality he has. But it's not just him, today in particular he was the most important player for us."
Of his successful penalty in the shootout, Fernandes said: "I thought the goalkeeper would hold out until the end, because he usually does. What he did made my decision easier, because he ended up having to decide a little earlier."
Fernandes also insists Sunday's victory has them better prepared for next year's World Cup.
He added, "We want to be at the World Cup and try to win another competition. Portugal don't enter anything to lose. But first we have qualification ahead of us and we're going to do everything we can to win, put on a show and make the Portuguese more and more proud of us."