Perhaps Sir Alex Ferguson had reminded his Manchester United players about what had happened the last time they played here, on the final day of last season, and the malicious pleasure Sunderland's supporters had taken from that championship-deciding goal from Sergio Agüero. Yet Ferguson's team did not have to be particularly fired up. Their performance never rated anything more than six out of 10 but it was still enough to continue the transformation of this season's title race into something bordering a procession.

They moved 18 points clear of Manchester City while playing for long spells with the air of a team holding something back. Ferguson had left out Wayne Rooney, Patrice Evra and several others for the FA Cup quarter-final replay at Chelsea on Monday. One of them was Rio Ferdinand in a move that is unlikely to soothe any lingering bad feeling over his absence from England duty.

Yet Ferguson was entitled to take risks when the opposition is this moderate. Sunderland were poor in the extreme, going down to the latest addition to Titus Bramble's portfolio of own goals and unable to register a single shot on target until the fourth official was preparing the electronic board to show there would be six minutes of stoppage time at the end of the match. They had improved in the second half, but only in the context of how vapid they had been in the opening 45 minutes. For long spells they had looked a broken team.

Martin O'Neill's team have not won any of their last eight matches and, bereft of ideas, it is easy to understand why so many supporters are considering their position in the league with growing unease. O'Neill's teams are traditionally known for their enthusiasm, their ability to play above themselves and the old-fashioned desire to make it hard for superior sides. There was none of that here. United did not play anywhere close to their top level but they did not have to when their opponents were so vapid. "We're going to win the league," their supporters crowed. They will have cherished the opportunity to return some of the schadenfreude that came their way last May.

For Sunderland, it was a chastening experience. O'Neill stood forlornly on the touchline, with little of the energy of old. There was once a time when he was almost as entertaining to watch as the football. His enthusiasm could lift an entire crowd and, in happier times, it felt as though his players would crawl against broken glass if he gave the order. His body language now is entirely different: arms folded, barely moving, the only flicker of emotion being the occasional show of annoyance about a refereeing decision.

Sunderland are certainly going to need some of the old O'Neill back if a difficult season is not going to get even more harrowing. With Steven Fletcher out for the season, their leading scorer here was Craig Gardner with six goals, four of which came from the penalty spot. Their crowd was just about as patient as might reasonably be expected. Yet it was unusual for this stadium to be so flat and the team did little to change it

They were certainly obliging opponents for a side trying to balance two games in the space of three days. Shinji Kagawa, in particular, excelled for United as they asserted their authority in the opening 45 minutes.

Nemanja Vidic exuded total control in the centre of defence and their most impressive player, however, was Alex Buttner, deputising for Evra at left-back and having his best game for the club. David de Gea had one alarming moment when his miskick went straight to a Sunderland player but was rarely troubled thereafter and handled the aerial bombardment well in the 10 minutes of the second half when Sunderland finally worked up a head of steam.

Ideally, United would have liked the goal to be awarded to Robin van Persie bearing in mind the Dutchman has been through a relatively barren spell. He had some lovely touches and does not look particularly short of confidence, yet he would ordinarily have buried the chance that came his way with the final kick of the match

The goal originated on the left. Van Persie had taken the ball on the byline then cut back on himself, with Phil Bardsley in close proximity. The Dutchman went for power, blasting a cross-shot between Bardsley's legs and the deflection from Sunderland's right-back sent the ball across the goalmouth. Bramble jutted out a right leg and the ball flew off his kneecap into the far corner.