Stern John got Sunderland's Irish tour off to a winning start, though Roy Keane's Black Cats had to work hard for their victory at Dalymount Park.
John, a 72nd minute substitute, finally broke the deadlock on 78 minutes when out-jumping Bohs 'keeper Josh Mimms to head home a Ross Wallace cross.
Earlier, new £5 million signing Michael Chopra missed a sitter before having a shot deflected over the bar by David Connolly.
Keane started five of his six new signings with Ireland international Paul McShane making his debut following his €2.2 million move from West Brom on Thursday.
Anthony Stokes, playing on the left wing, carved out the first opening of the night when checking back across Mark Rossiter to put over a cross fellow Irishman Daryl Murphy just failed to reach.
McShane's first task a the other end was to clear off the line from Darren Mansaram on 16 minutes after the Bohs striker had out-muscled Black Cats skipper Nyron Nosworthy to get to Brian Murphy's long kick-out.
Stokes' quick feet out-foxed Rossiter again on 32 minutes, but the Dubliner fired inches over the bar.
Stokes again carved an opening for Daryl Murphy to volley over on 54 minutes as Sunderland upped the tempo in the second half.
McShane showed his ability at both ends inside two minutes just past the hour mark. First, he made a crucial block tackle on Mansaram after he had broken through following a one-two with Chris Kingsberry down the left.
McShane's threat from set-pieces was then evident when he rose to head just wide from Kieron Richardson's corner.
Bohemians: Murphy (Mimms, 31); Rossiter, Burns (Rice, 81), Pooley (Rafferty, 66), Powell; McGinley (Moran, 74), Hunt (McCann, 49), O'Donnell (Brady, 87), Richardson (Kingsberry, 57); Fenn (Harkin, 79), Mansaram (Kelly, 71).
Sunderland: Fulop; Halford, Etuhu, McShane, Wallace; Edwards, Etuhu, Richardson (Collins, 76), Stokes (Whitehead, 62); Murphy (Connolly, 66), Chopra (John, 73).
Referee: Dave McKeon (Dublin).