Adam Rooney maintained his remarkable scoring spree in a green shirt with a hat-trick inside 16 minutes to give the Ireland Under-19s the perfect start to their qualification hopes at United Park.
With a scoreless draw between Germany and Hungary a welcome result in the earlier game, if got so much better for Ireland as they found themselves two goals to the good inside six minutes to utterly bamboozle the bewildered Bulgarian before they’d broken sweat.
And it was Stoke City striker Rooney who then completed his hat-trick ten minutes later to give him a remarkable ratio of having scored a goal a game in his 19 appearances for Ireland.
Bulgaria scarcely knew what hit them when they found themselves behind inside the third minute. A tackle on Anthony Stokes by Velin Damyanov only succeeded in sending the ball low across to the back post where Rooney arrived to side foot past keeper Nikolay Mihaylov.
An unconvincing defence then gave away a penalty when Ivan Ivanov hauled down Stokes. Robert Bayly's spot kick was well parried by Mihaylov, but Rooney was first to the loose ball to shoot home.
The hat-trick arrived on 16 minutes. Stokes cleverly dummied Jimmy Ryan's pass and Rooney collected, turned sweetly 20 yards out, before beating Mihaylov with a low shot to the corner of the net.
Ireland continued to dominate with Stokes shooting wide before half-time.
It remained very much one-way traffic into the second half. Stokes, put clean through from keeper Stephen Henderson's clearance, shot wide before Bulgaria came alive to create two quick chances just before the hour mark.
Henderson, son of Cobh Ramblers' boss Stephen, first put a shot from Dimitar Iliev out for a corner off his feet before smothering at the feet of Iliev within a minute.
But Ireland hit back with Rooney being deprived of a fourth goal by the feet of Mihaylov on 73 minutes before Stokes showed greatly feet to get in a shot that was also well stopped by the overworked Bulgarian keeper.
The one blot on the copybook for Ireland is that Bayly received a yellow card for taking a free-kick too quickly on 67 minutes and, having carried a booking through from the preliminary qualifiers, is now out of the second game with Germany at Dalymount Park on Wednesday night.
The Germans drew 0-0 with Hungary at the Carlisle Grounds yesterday afternoon.
Republic of Ireland: Henderson (Aston Villa); Davies (Reading), Lowry (Aston Villa), Spillane (Norwich City), Nolan (Blackburn Rovers); Judge (Blackburn Rovers), Ryan (Liverpool), Power (Nottingham Forest), Bayly (Leeds United); Stokes (Sunderland), Rooney (Stokes City).
Subs: Madden (Leeds United) for Davies (53 mins.), Redmond (Nottingham Forest) for Henderson (77 mins.), Treacy (Blackburn Rovers) for Stokes (83 mins.).
Bulgaria: Mahaylov; Vasilev, Damyanov, Lemperov, Ivanov, Hristov, Divulger (Pavlov, 36 mins.), Baltanov, Filipov; Iliev, Ognyanov.
Subs: Abrashav for Hristov (30 mins.), Yordanov for Iliev (76 mins.)
Referee: B Duartepaixao (Portugal).