First International goals for Alan Browne, Kevin Long and James Collins in the second half was enough to give Ireland the victory after Bulgaria had levelled with an Ivelin Popov penalty.
The Boys in Green were fortunate not to go behind in the opening minutes as Georgi Pashov and Kristian Dimitrov both failed to trouble goalkeeper Mark Travers on his Irish debut with their free headers from close range.
Ireland responded well to those let-offs and Alan Judge twice went close to scoring at the other end but after seeing a header of his own drop onto the top of the net, he scuffed a weak shot straight at goalkeeper Hristo Ivanov from a decent position.
Mick McCarthy’s side dominated the rest of the first half but they failed to create a decent goal scoring opportunity of note although Ronan Curtis’ cross from the left almost found the bottom right corner before the break but Ivanov did well to stop it.
The Republic would take the lead in the 56th minute when Alan Browne rolled home his first international goal from a couple of yards after Scott Hogan mishit his rebound from Ronan Curtis’ saved effort.
But they would only be ahead for 11 minutes as Bulgaria equalised when substitute Ivelin Popov blasted his penalty into the top left corner after captain John Egan fouled Bozhidar Kraev inside the box.
But Ireland would snatch the win in the closing stages as Kevin Long headed Jack Byrne’s corner in at the back post before James Collins fired Enda Steven’s cross into the roof of the net.
REPUBLIC OF IRELAND: Mark Travers (Kieran O’Hara 75); Cyrus Christie, John Egan (captain), Kevin Long, Conor Hourihane (James McClean 68); Alan Browne, Alan Judge (Jack Byrne 59), Josh Cullen; Callum O’Dowda (Enda Stevens 76), Scott Hogan (James Collins 59), Ronan Curtis (Jeff Hendrick 84).
BULGARIA: Hristo Ivanov; Ivan Goranov, Anton Nedyalkov (Vasil Bozhikov 59), Kristian Dimitrov (Vasil Panayotov 80), Georgi Pashov (Kiril Despodov 88); Simeon Slavchev; Daniel Mladenov, Georgi Milanov (Ivelin Popov ht), Kristiyan Malinov (Georgi Terziev 80), Nikolay Dimitrov Wanderson 59); Bozhidar Kraev.
Referee: Tobias Welz (Germany).