Manchester United have a golden opportunity to silence the critics proclaiming their demise when the Premier League leaders travel to struggling Sunderland tomorrow. By the time the Red Devils kick off at the Stadium of Light, they could have been surpassed by Liverpool, who host Blackburn Rovers in an earlier game, but a victory for the champions would immediately restore them to top spot.

Including Wednesday's error-strewn 2-2 draw with Porto in the UEFA Champions League, Sir Alex Ferguson's side have now conceded ten goals in their last four matches and pundits are beginning to question their ability to get over the finish line in the league and in Europe. United's recent wobble, which has included just one win in four matches, has allowed both Liverpool and Chelsea, who trail by four points, back into the title race.

It's not that the goals we are conceding are great goals from our opponents. We have to sort that out.
Manchester United goalkeeper Edwin van der Sar

A key factor in the Old Trafford club's recent slump has been the sudden defensive meltdown. Ferguson has had to endure regular injuries and Rio Ferdinand continues to be troubled by a groin problem that also affects his back, while Jonny Evans sustained a groin injury in the draw with Porto and is also set to miss the Sunderland game.

United are still without Wes Brown, who has missed much of the season with an ankle injury, while the young Brazilian right-back Rafael da Silva is unlikely to play again this season due to a similar injury. To add to United's problems, Wayne Rooney is doubtful for the Sunderland meeting with a rib injury and Dimitar Berbatov is set to be missing for another week.

Despite United's problems, they should still be strong enough to beat Sunderland, who are just three points clear of the relegation zone after winning only one of their last eight league matches. United's Dutch goalkeeper Edwin van der Sar is adamant they can turn it around and has challenged his team-mates to rediscover their fine defensive form.

"It's not that the goals we are conceding are great goals from our opponents," he said. "Of course, we have to sort that out and start focusing on what we did very successfully for a long time this season.

"We need to get back to that way of defending and then we should be okay. We had a hard game on Sunday, and again on Tuesday. We need to make sure we focus again for Saturday against Sunderland."

Scoring problems
Sunderland manager Ricky Sbragia is under pressure after his side failed to win any of their last six matches and he is likely to be without defender George McCartney and striker David Healy, who have calf and groin problems respectively. Finnish midfielder Teemu Tainio could make a first appearance since suffering a knee injury in February.

A lack of goals has been the key to Sunderland's slump. The club's two main strikers Djibril Cisse and Kenwyne Jones have not managed a goal between them in more than a month.

We're better off than three teams below us so we're not in the worst position, we roll our sleeves up and fight for every point possible.
Sunderland goalkeeper Craig Gordon

Yet Scotland goalkeeper Craig Gordon is adamant that Sbragia's team can pull themselves out of trouble. "There's no escaping it, and that's where you see the true character of the players," he said.

"We're better off than three teams below us so we're not in the worst position, we roll our sleeves up and fight for every point possible. We've got players in this dressing room that have experience of last year and we're desperate to ensure we get the same outcome this season."