And what made it all the more remarkable was that the Chelsea striker managed it despite the fact his luggage did not arrive in Portugal and he had to send out an SOS for new footwear.
The ex-Celtic forward was unplayable for large chunks of the game and destroyed the home side with his finishing.
However, the young Dark Blues folded in the second half and lost three goals in 14 minutes to suffer a defeat in Ricky Sbragia's first game as Under-21 caretaker boss.
Portugal won it with a disputed penalty, but the former Sunderland gaffer was delighted by his team's display.
He said: "Islam played exceptionally well and was given a lot of good service. He's so quick and has great feet and he deserved his goals, but we wanted him to get his hat-trick.
"He has great belief in his ability and showed he can make the step up from the Under-19 Scotland side where he has been scoring goals.
"He has shown he can handle it and his finishing was exceptional. His boots didn't arrive at the airport when we landed and I told him to phone Puma and get them to send them a pair and that's what they did.
"Credit to Portugal for the way they came back at us and we were at fault with some decision-making, but I'm delighted with my players. It's the first time I've been in caretaker charge of them and they gave me their all.
"I told them at full-time to take the positives from the game. In the first half we were the dangerous side and created a host of chances.
"It was never a penalty for their third goal, but referees get things wrong and their manager has apologised to me over it. I'm sad for them, but that's football."
The young Scots got off to a dream start in the 12th minute. A Kevin McHattie corner from the right was glanced into the net by Feruz to stun the home crowd.
And it was no surprise when Scotland went two goals up nine minutes later. Hearts' Jason Holt flicked the ball on to the onrushing Feruz, who raced past Portuguese keeper Luis Ribeiro by flicking the ball over his head and effortlessly tucked the ball into the empty net.
Scotland were assured, confident in possession and were dictating play, but it wouldn't last.
The home side pulled a goal back eight minutes into the second half when slack marking at a corner allowed Paulo Oliveira to score with his head.
Portugal's tails were up and they equalised in the 57th minute when Aldair chipped the ball over the body of sub Scotland keeper Jordan Archer.
It got worse when ref Bruno Esteves awarded a harsh penalty against the Dark Blues for an alleged handball in the box against Scotland captain Lewis Toshney.
Sergio Oliveira tucked the spot-kick away.