However, he has warned Sir Alex Ferguson's men have a habit of coming good in the end. By his own admission, Ferguson believes the Red Devils have yet to play to their full potential, but nevertheless returned to the top of the Premier League following Saturday's 7-1 demolition of Blackburn at Old Trafford. United are unbeaten so far, with seven draws and eight wins from 15 league games, and have yet to concede a goal in Europe. Ferguson is set to make several changes for Tuesday night's Carling Cup quarter-final at Upton Park, with the likes of Javier Hernandez, Chris Smalling, Wes Brown and goalkeeper Tomasz Kuszczak all keen for a chance to impress. Grant went head to head with Ferguson in the 2008 Champions League final, when his Chelsea side were beaten on penalties in Moscow as United added European glory to their domestic title. The Israeli feels while the Red Devils are a class act, to extend the current unbeaten record through to May is perhaps too big an ask. "It has happened before with Arsenal, but I don't think it will [again]," said Grant. "What happened with Arsenal was exceptional. I don't believe there is a team which can last all the season without losing." The former Portsmouth boss, however, is in no doubt United will be leading the chase for honours again in 2011. "When I was at Chelsea, Alex [Ferguson] described that season as the best season ever - but even then they did not start so well," Grant said. "You don't need to be at your best in the first few months, but at the end of the season. "Alex is very clever. He does it every year. I can't remember one season when United started with full power." West Ham have worries at the other end of the table, as they remain bottom despite Saturday's morale-lifting home win over Wigan. Grant is set to utilise all of his squad on Tuesday night, aiming to protect key men like Scott Parker, who has been troubled by a chest infection, against burnout. Defender Lars Jacobsen is cup-tied after playing for Blackburn in their second-round win over Norwich before his August move to the Hammers, but midfielder Kieron Dyer could return from a hamstring injury. However, the Irons boss also knows the importance of the fixture, having reached the last eight with hard-fought victories at Sunderland and against Stoke. "Many of the players we have in the squad this season have had long-term injuries, so we have to manage them differently," Grant said. "We are doing all we can so they can play, sometimes we succeed, sometimes not. "It is not very often that West Ham comes to a quarter-final of any competition, so we will try to win this game." Academy product James Tomkins impressed alongside Matthew Upson at the centre of West Ham's defence against Wigan, having spent a few days working with new coach Wally Downes. The 21-year-old is hoping the Irons can take momentum into the clash against United. "The game is massive for the fans. It doesn't get much bigger than the cup quarter-final," Tomkins said. "The mood is good in the dressing room. It is nice to get the win, to see the lads buzzing. "After a game when you win there is no better feeling and hopefully we can just carry this on against United." Saturday's match against Wigan had been labelled the 'save our season' game by the Upton Park board, who reduced ticket prices to help obtain a bumper crowd of just over 34,000. Grant feels the demanding Boleyn Ground faithful can play their part against United. "The fans are great. They saw us give a poor performance last week at Liverpool after going a long way on a cold day," said the West Ham manager. "I am sure they will continue like this on Tuesday and will do everything to support us."
