Playing in all navy blue, the Scots started with efficient passing, setting the tone to the European Champions that the evening would not become an easy one.
The Portuguese once on the ball did show touches of class and skill, Eder did create a couple of chances for himself. One which rolled past the post, the other well saved by Gordon. Yet majority was snuffed out by Scotland's hardwork. Naismith would be unlucky with a header which went wide of goal.
But just before the break, a ball from the left went through the legs of O'Donnell to be met by Helder Costa finishing from two yards.
The second half began with both sides canceling each other out. A diving header from Scott McKenna zoomed inches wide of goal. Scotland were left to rue that miss. Portugal waited patiently to create their chance. A free-kick into the box from the right was met by the head of Eder, who made no mistake to put his country 2-0 to the good. The men in white showed their class once more and with seven minutes to go, playmaker Bruma received the ball, ran forward into the box, cutting inside releasing a ferocious shot into the top corner.
With the last few seconds of the game remaining, Scotland found the net. Graeme Shinnie put in a tackle, ran towards the Portugal goal, finding Mackay-Steven, who's lovely back heel found Naismith -curling the ball past Beto from twelve yards out.
Scotland: Gordon; O'Donnell, Hendry, McKenna, Robertson; Forrest, Armstrong, McGinn, C McGregor; McBurnie, Naismith
Substitutes: A McGregor, McLaughlin, Shinnie, Russell, McDonald, Devlin, Mackay-Steven, Christie
Portugal: Beto; Cedric, Neto, Dias, Rodrigues; Danilo, Oliveira, Fernandes; Bruma, Eder, Costa
Substitutes: Ramos, Cancelo, Mendes, Sanches, Silva, Carvalho, Silva, Neves, Rui, Pizzi, Fernandes