
Barney Stewart scored his third goal in two games for Scotland Under-21s
Scotland secured third place in European Under-21 Championship qualification Group B thanks to goals in either half by Barney Stewart and Bobby Wales in Bulgaria.
The two sides, who started the night level on points, had already failed to qualify for next year's finals behind Portugal and the Czech Republic.
But the visitors were looking to build on Wednesday's 5-2 win over Azerbaijan - their first game under new head coach Tony Docherty.
They were without Findlay Curtis after the Rangers winger was recalled to the senior squad following his four assists at Rugby Park but dominated the early possession before the breakthrough eventually came just after the half-hour mark.
Curtis' replacement, Dunfermline Athletic forward Andrew Tod, won the ball in midfield and found Stewart to send a powerful, low-flying 20-yard drive past goalkeeper Plamen Andreev.
Bulgaria almost immediately responded to the West Bromwich Albion striker's third goal in two games, Martin Georgiev denied by a save at full stretch from Rory Mahady, who had started instead of Liam McFarlane in goal.
Midfielder Antoan Stoyanov should have done better than head wide from 10 yards as the hosts applied pressure at the start of the second half, but Scotland regained control and Dylan Lobban was twice denied by Andreev twice in quick succession.
Lobban denied Bulgaria an equaliser, blocking Tsvetoslav Marinov's shot on the line, with Filip Gigov stabbing the reply wastefully wide.
Frustration boiled over for the hosts, with defender Simeon Shishkov sent off for a late challenge on Lobban and Scotland assistant Steven Naismith red carded in the aftermath.
There was still time for Stewart to slide the ball into the path of substitute Wales for the striker's second goal in two games as the visitors ended their campaign on a high.