FA Premiership/ Manchester Utd 2 Sheffield Utd 0: There have been times this season when Manchester United have blown away their opponents with the sheer quality of their football and times when they have won without hitting top form.

The supporters inside Old Trafford may be disappointed that this was not one of the more illuminating nights but it was probably unrealistic to expect the Premiership leaders to scintillate every week and Alex Ferguson's face was still suffused with a broad smile at the final whistle.

"Chelsea are going to catch you," the Sheffield United supporters sang, but the gap at the top of the table has been restored to six points after goals at the start of each half from Michael Carrick and Wayne Rooney and there are now only five games left.

Neil Warnock's team were denied an obvious penalty when Gabriel Heinze brought down Luton Shelton - an offence for which the Argentinian should have been sent off - but the league leaders were still by far the better side and the pressure is switched to Jose Mourinho's team as they prepare to play their game in hand at West Ham tonight.

Mourinho sent Ferguson a congratulatory text message last week after their teams had reached the Champions League semi-finals. On this occasion, however, it is difficult to imagine the Chelsea manager being so magnanimous. He is particularly unlikely to have been impressed by Neil Warnock's decision to field a deliberately weakened side, with Saturday's relegation skirmish against Charlton Athletic in mind.

There was logic to Warnock's thinking but also a certain amount of hypocrisy given he had described Middlesbrough as "scandalous" for using the same strategy against Manchester City before an FA Cup quarter-final at Old Trafford last month.

Warnock is not a man to wave a white flag but the gulf in class between the two sides was predictable and it was a surprise the home side did not ram it home more emphatically once Michael Carrick latched on to Ronaldo's short and perfectly-weighted through ball to score with an adroit finish over Paddy Kenny. At that stage some of the visiting players had not even a scuff of mud on their knees but thereafter they defended with typical spirit and tenacity, quick to the ball and strong in the tackle - sometimes too strong for Ferguson's liking.

Patrice Evra was added to Ferguson's long list of injured defenders - he was already missing both his first-choice centre halves - after being scythed down by Colin Kazim-Richards and one challenge by Matthew Kilgallon ripped Alan Smith's shorts wide open.

There had been no place in the home side's starting XI for Edwin van der Sar, whose relegation to the bench can be attributed to his first prolonged period of indifferent form in two otherwise impressive seasons. A better side than Sheffield United might have done more to examine his replacement, Tomasz Kuszczak, because the Pole is far from impregnable.

Apart from a few flashes from Shelton, however, the visitors seldom caused this makeshift defence problems and the game was all but ended as a contest four minutes after the break, courtesy of Rooney's 20th goal of the season. The goal was classy in its creation and clinical in its execution. Ryan Giggs had spotted Rooney peeling away from Chris Morgan and his ball over the top was beautifully measured. Rooney's finish was of the utmost quality, a powerful and instinctive right-foot shot beyond Kenny.

It was a moment that soothed any lingering nerves in the crowd and, oozing with renewed confidence, the home attackers went in search of another large score. This was not a night, however, when they came close to touching the exhilarating heights that had been seen in this stadium in the rout of Roma and they were relieved not to concede a penalty when Shelton ran clear in the 68th minute and Heinze dived in from behind. The Argentinian was not even close to connecting with the ball.

• Guardian Service

MANCHESTER UTD: Kuszczak, Fletcher, Brown, Heinze, Evra (Richardson 21), Ronaldo, Carrick, Scholes, Rooney, Giggs (Solskjaer 80), Smith. Subs not used: Van der Sar, O'Shea, Cathcart. Booked: Smith, Rooney, Ronaldo.

SHEFFIELD UTD: Kenny, Geary, Morgan, Kozluk (Armstrong 77), Kilgallon, Jagielka, Webber, Montgomery, Tonge, Kazim-Richards (Gillespie 75), Shelton (Nade 89). Subs not used: Alan Quinn, Fathi. Booked: Geary, Morgan, Armstrong.

Referee: R Styles(Hampshire).