Nemanja Vidic may never get the praise he deserves but the defender is priceless in manager Sir Alex Ferguson's eyes.

If United were to manage another clean sheet at Bolton on Saturday, they will equal Chelsea's Premier League record of 10 on the trot.

It is a run to be proud of, considering Rio Ferdinand and Patrice Evra have been missing for long spells - while Rafael and Gary Neville have been alternating at right-back.

Apart from Edwin van der Sar, Vidic has been the constant presence.

The Serbian has weighed in with a few crucial goals too - and with Jonny Evans a major doubt for the Reebok Stadium encounter, Ferguson is thankful to have Vidic around.

"We are the kind of club where attention always goes on to the star players," said Ferguson.

"I always used to say Denis Irwin would give us eight or nine out of 10 every week, but he never got a mention when the praise was being given out.

"We all knew the value of him, and it is very much the same with Vidic. He has been a fantastic performer for us."

Signed from Spartak Moscow on Christmas Day 2005 for £7.2million, Vidic was introduced to life at United at the same time as Patrice Evra.

Having not played for a month because of the annual Russian winter break, it was no surprise Vidic was somewhat rusty when he made his debut against Blackburn.

Like Evra, it took Vidic quite a time to adjust. Now, he is one of the most reliable defenders in Europe.

"He came at a bad time," reflected Ferguson.

"He had not played since the beginning of that December and maybe he was not ready for the cut and thrust of the Premier League.

"I know Patrice thought the world had fallen in after he had made his debut - but you see him now. It is the same with Nemanja."

Ferguson has drafted 19-year-old James Chester into his squad - although even if Evans does not make it, the Scot would be keen to avoid handing the young Warrington-born academy graduate his senior debut against a side as physical as Bolton.

United do have a decent record at the Reebok Stadium, although they did lose last season when Nicolas Anelka netted the only goal of a stormy affair in which Ferguson's half-time confrontation with referee Mark Clattenburg earned him a two-match touchline ban.

The Red Devils chief does admire Bolton's battling qualities and has plenty of praise for the work Gary Megson has done on a limited budget, after Sammy Lee's disastrous 11-match reign was brought to an end.

"Bolton are survivors," said Ferguson.

"Gary Megson has done well, taking over the residue of Sam's [Allardyce] legacy. That was not an easy one to try and match.

"There was a lot of criticism when he got the job, but he kept Bolton up last year when I thought it was an impossible situation."

Confirming Wayne Rooney's hamstring injury will keep out for a maximum of four weeks but most probably three, Ferguson is also keeping his fingers crossed Carlos Tevez comes through a 10am fitness test - along with Evans.

If both miss out - and it is a definite possibility - it will be a patched-up United side that takes the field, Cristiano Ronaldo in line for a striking berth providing he shakes off a minor knock.

It is not the best backdrop to a derby. But Ferguson acknowledges the prize - a place at the top of the Premier League table for the first time this season - is well worth winning.

"It is an incentive," he said.

"Obviously the bigger incentive is to win the league, and I have said all along points get dropped.

"What we are trying to do is put ourselves in a good position for the run-in.

"I would not say a victory tomorrow would give us a psychological edge - but it won't do us any harm.

"Being at the top of the league is the best place to be. It doesn't matter if it is the first game of the season or the 20th."