Queen's Park lost to Elgin City and thus confirmed Rangers as Scottish Third Division champions.
With the Spiders had to avoid defeat to prevent Ally McCoist's men clinching the title on Saturday.
But Stuart Leslie's second-half penalty gave Elgin the lead at Hampden and Queen's Park could not recover.
The hosts remain well placed to secure a promotion play-off place as Elgin boost their own play-off hopes.
Craig Gunn tested Queen's Park keeper Neil Parry early on and the hosts threatened through Lawrence Shankland, Blair Spittal and Andrew Robertson.
Elgin were awarded their spot-kick James Brough fouled Paul Millar and Leslie fired home.
Spittal had the chance to level moments later but was off target.
Six points now separate Elgin from the play-off zone but the Borough Briggs side have a game in hand.
Queen's Park: Parry, Gallacher, Brough, Bradley, Robertson, McParland, Longworth, Anderson, Spittal, Shankland (Quinn 64), Connolly (Davison 64).
Subs Not Used: Lochhead, Gibson, Giuseppe Capuano.
Booked: Brough, Parry.
Elgin City: Malin, Niven, Crighton, Duff, McMullan (Harkins 84), Gunn, Cameron, Nicolson, Moore (Morrison 69), Millar, Leslie.
Subs Not Used: Black, Beveridge, McLean.
Booked: Crighton, Nicolson, Morrison.
Goals: Leslie 57 pen.
Ref: Colin Steven