Ivelin Popov struck the only goal as Bulgaria delivered a huge blow to Wales' hopes of qualifying for Euro 2012 last night.
The Bulgaria striker lashed in a shot off the post after 48 minutes at the Cardiff City Stadium to condemn Brian Flynn to defeat in his first match as caretaker manager.
Welsh woes were compounded in injury-time when Chris Gunter was sent off for a cynical foul on Dimitar Rangelov.
After two defeats from two games in a group that also includes England, Wales' chances of finishing even second look slender. Yet for much of the first half they had looked sharp and enterprising. Playing the attacking football, they carved out clear-cut chances for Gunter and David Edwards that should have been taken.
Bulgaria upped the tempo after the break and threatened to overrun the Welsh. Gunter bravely blocked a Martin Petrov shot as the visitors powered forward but Wales could not hold out for long.
Popov fired Bulgaria into the lead when he collected the ball from Nikolay Bodurov in the box and beat Wayne Hennessey with aid of the woodwork. It almost got worse for Wales as Stiliyan Petrov tested Hennessey from 40 yards with a fierce shot and Martin Petrov then broke clear only to miss the target.
Flynn was facing a stern examination but Steve Morison almost hauled his side level when he skipped a challenge on the edge of the box and forced Nikolay Mihaylov to push away a strong drive.
Chavdar Yankov almost grabbed a second for Bulgaria in the final minute but the Hennessey was equal to his low shot.