Jason McGuinness spared Sligo Rovers' blushes with a second-half double to dispose of non-league Pike Rovers at the Showgrounds.
The centre-back netted twice inside six second-half minutes, after the Limerick side had taken a shock lead through Colm Carroll's header.
David Ryan also found the net for Pike with five minutes left, but a deflected third for the holders from substitute Raffaele Cretaro ultimately saw them through.
Sligo's Alan Keane missed from the spot midway through a tentative opening half, after Daryl Horgan was taken down. Keane went for power but saw his effort crash back off the bar.
The Limerick side took a shock lead on 58 minutes. Eoin Hanrahan did the hard work down the left before crossing for Carroll to head home.
But the lead lasted just three minutes, when McGuinness forced the ball home from close range for his first goal for the club. His second arrived when he headed a corner to the net, before Cretaro's deflected shot wormed its way past Gary Neville.
But the holders had to endure a nervous final five minutes after Ryan pounced to score.
Sligo Rovers --Clarke, Russell, Kirby, Greene, Ventre, Foran, Keane, McGuinness, Davoren, Horgan, Blinkhorn.
Pike Rovers -- Neville, Colbert, O'Donovan, Mullins, Cleary, Kavanagh, Hartnett, Hanrahan, Ryan, Tierney, Carroll.
Ref -- P McLoughlin (Monaghan).