Emanuele Giaccherini's first goal for Sunderland was enough to give them the lead at half time against Peterborough United in the League Cup.
The club were beginning life after Paolo Di Canio since his sacking as manager and it was nearly a start to forget as Keiron Westwood was called into action early to keep out Danny Swanson's low drive.
The hosts nearly forged a lead of their own as Sebastian Larsson tried his luck, but the Swedish international was wide of the target with his effort.
Posh were dealt a blow when Lee Tomlin, whose early form so far this season has attracted interest from Celtic, was forced off injured after a challenge from Ki-Sung Yeung, for which the Korean player was booked.
Sunderland continued to pressure the visitors as the game progressed and Lee Cattermole almost broke the deadlock but couldn't connect with Larsson's corner as the Black Cats continued to squander promising attacking positions.
The hosts finally took the lead on 34 minutes, when Cattermole's precise cross found Emanuele Giaccherini who bagged his first goal for the Wearside club.