Glentoran's young guns were taught a harsh lesson as their Setanta Sports Cup run effectively came to an end in Sligo.
After a brave and battling victory over two legs against St Patrick's Athletic in the first round Eddie Patterson's side will do little more than fulfil a fixture when the second leg of this time comes around next week, after suffering a 5-0 hammering.
Sligo debutants Anthony Elding and Evan McMillan were among the goals, Lee Lynch scored a brace and Ryan Connolly also got his first goal for the club as Rovers ran riot.
Glentoran had only five of the players that started their Irish Cup game on Saturday, with Sean Ward, Mark Clarke, Jay Magee and Stephen Carson absent, and Andrew Waterworth and Richard Clarke on the bench.
Rovers had the ball in the net after just 130 seconds, with Lynch superbly volleying Elding's knockdown to the net from inside the area.
Elding had an effort ruled out for offside shortly after, but got the goal his play deserved when heading home Lynch's cross from close range on 20 minutes.
The visitors looked tired and spent most of the evening chasing shadows. And they were unable to keep up with the intelligent running of David Cawley, who broke down the right on 37 minutes before picking out Ryan Connolly to flick home.
Connolly's cross from the left then rebounded kindly for Lynch to fire his second, and the Bit O' Red were four clear by the break.
They did not let up in the second half, with Evan McMillan heading home Joseph Ndo's cross on 53 minutes, and Cawley denied an audacious backheel goal by Glentoran keeper Elliot Morris.
The introduction of Waterworth, Clarke and Daniel Burns breathed a bit of life into the Glentoran challenge, but the damage was already done, leaving the Belfast club with a uphill task in next Monday's second leg.
A great night for Rovers fans got even better when the club unveiled Kieran Djilali as a new addition the squad.
The former Crystal Palace and Wimbledon midfielder has signed a one-year deal at the club, with the option of a second year.
Sligo Rovers: Rogers, Keane, McMillan, Peers, Gaynor, Ndo (Millien 62), Lynch, Cawley, Connolly, Greene (Martin 74), Elding (Cretaro 62).
Glentoran: Morris, Nixon, Birney, Bradley, Hill, Callacher (R Clarke 68), McAlorum, McGuigan, O'Hanlon, Murray (Burns 77), McComb (Waterworth 58).
Referee: Raymond Crangle (Belfast).