Injury-ravaged Manchester United are limping towards the Barclays Premiership title finishing line as a routine home win over Sheffield United was accompanied yet another defensive fitness problem.

Patrice Evra was forced off in the first half following a crude lunge by Colin Kazim-Richards, leaving Sir Alex Ferguson without a single member of his first-choice defence, including keeper Edwin van der Sar.

Yet nothing, it seems, will halt United's drive for the championship.

After Michael Carrick's early opener, Wayne Rooney drilled home a brilliant second at the start of the second half.

It takes Rooney's goal tally for the season to 20, just one adrift of Cristiano Ronaldo - who had a quiet night by his own high standards.

The result leaves Chelsea six points adrift heading into their trip to West Ham on Wednesday, but Ferguson's most immediate priority tomorrow will probably be a body count rather than worrying about what Jose Mourinho and his team get up to.

In the end, even with possible starters John O'Shea and Rio Ferdinand not included, Ferguson opted against handing 18-year-old Craig Cathcart his debut.

Instead, the United boss trusted the right-back role to Darren Fletcher, hoping the Scot's extra experience would make up for his complete lack of familiarity with the position.

With Wes Brown and Gabriel Heinze occupying the central defensive roles and Tomasz Kuszczak handed a rare start in goal due to Van der Sar's nose injury, United were not so much down to the bare bones as the marrow. And the situation got worse after just 20 minutes.

The tackle by Kazim-Richards on Evra did not even warrant a yellow card from Rob Styles, which was a surprise and set the tone for what was a robust opening period in which Rooney appeared to be on a one-man mission to get himself into trouble.

The England striker did eventually get a caution for hauling down Phil Jagielka on his follow-through after just failing to wipe out Michael Tonge.

But given the way he was flying around the pitch seemingly intent on getting stuck in and the positive impact he was to have, half-time came at a good time for the 21-year-old.

The same was also probably true for Kieran Richardson, who had been introduced as Evra's replacement but whose desire to get forward led to gaps appearing at the back.

As in the FA Cup semi-final with Watford on Saturday when Ferdinand picked up his groin strain, the one saving grace for United was that by the time Evra departed, they were already in front courtesy of Carrick's fourth goal in six games.

Hardly a renowned scorer when he arrived from Tottenham, the £18.6million midfielder has suddenly hit form.

After Ronaldo had found him with an inspired short pass, Carrick lifted his shot over Kenny to give the hosts a perfect start.

Had Rooney not smashed a shot straight at Kenny on United's next attack, the points would have been wrapped up there and then.

Instead, the hosts were forced to endure a few nervy moments, with Luton Shelton to the fore on his first Premiership start, before Rooney eventually bagged a second four minutes after the break.

Two Champions League goals and a couple against Watford had already indicated Rooney is not suffering the kind of form crisis some have suggested.

His latest finish, one touch to control Ryan Giggs' chipped pass and a second to blast the ball into the corner, merely emphasised the point.

While the visitors were sprightly foes, they were repeatedly indebted to Kenny for keeping the score down.

For a big man, Kenny showed admirable agility to get down to his near post and deny Ronaldo, then needed all his strength to remain standing as Alan Smith slammed a shot into his chest.

Another save from Ryan Giggs followed, although by then, Styles had made his most important non-decision, somehow failing to spot Heinze getting nowhere near the ball as he chopped down a goalbound Shelton.

If the penalty award had come, Heinze would surely have been sent off too, bringing with it an automatic three-match ban that would have ruled him out of key trips to Everton and Manchester City.

Given the defensive crisis unfolding in front of his eyes, Ferguson's men might have struggled to cope. As it was, they escaped on all counts.

Teams:

Man 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.

Goals: Carrick 4, Rooney 50.

Sheff 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.

Att: 75,540

Ref: R Styles (Hampshire).