Martin O'Neill's transformation of Sunderland's fortunes will face far stronger tests than that provided by Peterborough United, but the calmness, efficiency and confidence with which the Black Cats progressed into the fourth round of the FA Cup spoke volumes.
Not for a moment was there the slightest sense that Posh, a team with the second best scoring record in the Championship, were going to be capable of ruffling the visitors, let alone breaking them down. Sunderland were carefully solid in the first half, and after scoring twice in seven minutes at the start of the second, controlled the match in a manner which would have been unimaginable before O'Neill replaced Steve Bruce.
"I felt that in the first half we allowed Peterborough to have the ball in their own half a bit too much, though we still created some great chances," said O'Neill. "In the second we pressed them a bit closer to their goal, and were much more effective because of it."
The visitors were on top form from the start. With O'Neill stringing five across midfield, Phil Bardsley and Sebastian Larsson proved an effective combination down the right, and with the young winger James McClean a real presence on the left, the threat when they broke was considerable. Larsson should have done better than pull his shot wide after Bardsley's pass inside the full-back put him clear down the right, but coming in at the far post he could hardly have failed to score if Posh centre-half Ryan Bennett had not intercepted Craig Gardner's low cross. Gardner's header from a Larsson cross almost caught out Peterborough goalkeeper Joe Lewis, and the first half ended with Lewis saving a Bardsley drive to his left.
While Peterborough could take encouragement from the fact the game was still goalless at half-time, their fate was decided before the hour.
Larsson's free-kick, curled low into the penalty area, was intended to be a cross, but no one got a touch and Lewis could only watch flat-footed as the ball bounced in at his far post. Soon afterwards McClean's shot was deflected behind, and the 22-year-old rose to head Larsson's corner directly into the goal.
The rest of the match was a lesson in how a team can close a game down without overly exerting themselves, and the only disappointment for the visitors must have been their failure to take any more of their several chances.
Afterwards O'Neill was happy to praise Larsson and McClean, and was amused by the roar which greeted news that his club had drawn Middlesbrough at home in the fourth round.
"It could have been the fans or it could have been [club captain and former Middlesbrough player] Lee Cattermole. It's a great tie for us and for both sets of supporters, and we'll see if we can make being at home count," he said.
Peterborough manager Darren Ferguson said: "It's been a disappointing day because we didn't do ourselves justice. We didn't play at a quick enough tempo, but credit to Sunderland, they're a good side and on a bit of roll."
Peterborough: LEWIS 6/10, ALCOCK 6, ZAKUANI 7, WOOTTON 6, TOMLIN 6, BENNETT 7, BOYD 6, TAYLOR 6, ROWE 5, TUNNICLIFFE 5, SINCLAIR 5
Sunderland: MIGNOLET 6, LARSSON 7, RICHARDSON 6, KILGALLON 6, O'SHEA 6, BARDSLEY 7, SESSEGNON 6, CATTERMOLE 7, McCLEAN 8
Goals: Larsson 48, McClean 58
Substitutes: Peterborough United Kearns 6 (Wootton, 52), Little 6 (Rowe, 64), Newell (Sinclair, 71). Sunderland Meyler 6 (Vaughan, 70), Ji (Sessegnon, 77), Elmohamady (Gardner, 85).
Booked: Peterborough Bennett. Sunderland Cattermole.
Man of the match McClean. Match rating 5/10. Possession: Peterborough 41% Sunderland 59%.
Attempts on target: Peterborough 3 Sunderland 9. Referee M Atkinson (West Yorkshire). Attendance 8,954.