Leading 1-0 on aggregate, the Republic of Ireland had but one job on their home turf. However, they were unwilling to rest on their laurels and set about boosting their advantage inside the opening five minutes.
That approach nearly paid off when Jake O’Brien’s header from Robbie Brady’s corner needed clawing off the line by Plamen Iliev.
Next came the sort of sweeping attack that new Ireland boss Heimir Hallgrímsson was hired to employ, and Brady was again involved, this time cutting back for Troy Parrott, who cannoned an effort against the post.
For all the Boys in Green’s early endeavours, though, it was Bulgaria who took the lead after that initial flurry.
There was certainly nothing pretty about it, as Georgi Milanov’s volley from the edge of the area was deflected kindly into the path of Valentin Antov, who steered into the corner to silence the home faithful.
Ireland duly looked to respond quickly, and the first half ended with a feeling of deja vu when another O’Brien header from a Brady corner was denied, with goalscorer Antov this time being the man on the line to thwart the Irish.
With the tie firmly in the balance at the break, Ireland knew they had to find something special to re-establish their advantage, and they almost did within 10 minutes of the restart when Evan Ferguson strode clear, but his effort was tipped around the post by Iliev.
However, that only proved to be a temporary reprieve for Bulgaria, who were punished by Ferguson a matter of moments later, when the West Ham loanee played a swift one-two with Finn Azaz before firing an effort high into the roof of the net.
Hallgrímsson switched his tactical system 15 minutes from time, bringing on centre-back Jimmy Dunne for his international debut and switching to a back five in an attempt to shore up the defence.
Yet, he didn’t have to worry too much about coming under any late pressure, as his side wrapped the tie up in the closing stages when Adam Idah converted Mark Sykes’ delivery, which rubber-stamped Ireland’s League B ticket for the next UNL edition.
Bulgaria, meanwhile, are consigned to a third successive cycle in League C.
Flashscore Man of the Match: Robbie Brady (Republic of Ireland)