Peterborough 0-2 Sunderland
Sunderland produced a clinical display to breeze past Peterborough in the FA Cup third round as their resurgence under Martin O'Neill continued.
Black Cats winger James McClean hit the bar and Posh goalkeeper Joe Lewis made several saves in a goalless first-half.
Sebastian Larsson broke the deadlock soon after the break as his curling free-kick sneaked in at the far post.
The impressive McClean made it 2-0 with a header from Larsson's corner and Sunderland easily saw out the victory.
Last season, Sunderland lost to League One Notts County in one of the shocks of the third round, but there was a little chance of an upset at London Road as the Premier League outfit delivered a textbook demonstration of how to dispatch lesser-ranked opposition.
The Wearsiders, who have won four and drawn one of their six games since O'Neill replaced Steve Bruce, wore down their opponents by dominating possession and picked them off with two second-half goals.
O'Neill sung the 22-year-old McClean's praises in the build-up to the match and the Northern Irish manager's fellow countryman delivered a performance brimming with purpose and menace on the left wing.
Sunderland made a bright start with Larsson blazing across the face of goal before Craig Gardner dispossessed George Boyd and stung the palms of Lewis from long range.
Peterborough responded with a spell of concerted pressure in which Tommy Rowe had two shots in quick succession. The first struck his own player and the second whistled past the far post.
Then a barn-storming run from Paul Taylor took him right to the edge of the Sunderland box, but his shot flew wide.
At the other end, McClean drilled a left-footed shot against the bar from 20 yards, and Lewis had to be alert to keep out Gardner's header with his chest after it fizzed off the surface.
Peterborough had to weather a 10-minute spell with 10 men after a clash of heads between Gabriel Zakuani and Ryan Bennett resulted in the latter requiring lengthy treatment in the dressing-room before emerging with his head bandaged.
Two minutes into the second half, Sunderland took the lead as Larsson's free-kick from the left flew through a crowd of players and crept in at the far post.
Larsson missed a chance to make it 2-0 when he shot straight at Lewis, but the Swede atoned with the assist for the second goal.
His corner was whipped in to the near post where McClean rose above Zakuani to head firmly into the net.
There was still half an hour on the clock but Peterborough had the look of a beaten side about them and O'Neill could afford to use all three of his substitutions.
If anything, Sunderland looked the more likely side to score again, with Larsson finding space on the right and providing a superb swinging cross that just eluded the outstretched boot of substitute Ji Dong-won.
Sunderland boss Martin O'Neill: "I thought that in the first half we allowed Peterborough to play in their own half and when they ventured into ours we closed down.
"In the second half we closed down closer to their goal and became more effective.
"That's James McClean's third game now and he's just been magnificent. His ability, his willingness to work back and his all-round game you would think he had played 103 games not three games."
Sunderland goalscorer Seb Larsson on his side's recent revival: "Football is a funny game. We seem to be doing things well at the moment and we're getting a bit of luck when we need it. We want to carry on doing it."