Goals from Irish trio Anthony Stokes (2), Daryl Murphy and Roy O'Donovan gave Sunderland victory over Cobh Ramblers at Cork City's Turner's Cross ground.
Murphy gave Sunderland the lead when he cut inside and finished low into the far corner, before Stokes doubled the score in the 52nd minute with a shot which deceived Cobh goalkeeper James McCarthy.
Roy Keane - back at his first club - gave new midfield signing Teemu Tainio his first 45 minutes of action, with the Finn seeing plenty of the ball before the break in a role just in front of the Sunderland defence.
David Meyler, a recent signing from Cork, came on for his debut before Darren Ward saved a 66th-minute penalty from Max Cream, after the Sunderland goalkeeper had been adjudged to have brought down his fellow substitute.
Stokes made it 3-0 in the 78th minute when he tapped in from close range following good work on the left by youngster Nathan Luscombe, before another former Cork player - second-half substitute Roy O'Donovan - netted the game's final goal in the 89th minute.