Morton beat Ayr United 1-0 at Cappielow on Wednesday night to clinch the SPFL Development League West title.
Both sides went into the game knowing a victory would seal the silverware while a draw would have seen Airdrieonians clinch the trophy.
The only goal of an entertaining match, which saw good chances missed at both ends, came after 65 minutes when Jack Purdue coolly converted a penalty.
Recent Development League West winners
2016/17 Queen of the South