Northern Ireland could have led inside a minute when Seamus McCartan headed wide from close range, but they did break the deadlock with just eight minutes on the clock when Michael Duffy cut the ball back for Mikhail Kennedy to slot home at the back post.
Home goalkeeper Conor Brennan saved from Scotland captain John McGinn and Ryan Gauld as the visitors pressed for a way back into the game, but the equaliser did arrive on 34 minutes when Ryan Christie ran onto a ball over the top, controlled well and smashed past the Kilmarnock man.
Northern Ireland held on until half time but Jason Cummings should have put Scotland in front for the first time shortly after the restart when he fired wide after getting in behind the defence.
Dale Gorman made his side's task harder on the hour when he was sent off for picking up two yellow cards in the space of eight minutes, and the visitors took advantage immediately when Ipswich Town man Ryan Fraser met Gauld's ball to finish off a sweeping move.
Brennan denied Cummings and made a superb last-minute double save to keep Northern Ireland within sight of an equaliser, but a dominant Scotland were rarely threatened as they held out for victory.