At the other end 10 minutes later, Northern Ireland made their chances count as Shay McCartan found the back of the net from a free kick.
The hosts had an opportunity to equalise on the half-hour mark when they were awarded a penalty following a handball offence in the box.
Jason Cummings took the spot kick, but goalkeeper Conor Brennan went the right way and denied his opponent a crucial equaliser before the half-time break.
Scotland continued to pile on some pressure and it eventually paid off in the second half when Oliver McBurnie put his side on level terms with a 58th-minute strike.
Six minutes later, Cummings made amends for missing the penalty by slotting home to give Scotland a 2-1 lead in the qualifier, and he did not stop there.
The Hibernian forward added a third goal to Scotland's scoreline in the 78th minute, ensuring that his team left St Mirren Park with all three points.
Scotland remain fourth in Group 3, while Northern Ireland stay bottom and are still looking for their first win in the campaign.