Ruud van Nistelrooy believes Robin van Persie can be the key to Manchester United reclaiming the championship from Manchester City this season.

Van Persie has made an impressive start in his debut season, scoring 11 times. Van Nistelrooy, who scored 95 goals in 137 league starts for United, said of his countryman: "I spoke to him a little while before and I congratulated him on his fantastic start at the club and I wished him to continue like this. Its like he's been [at United] forever, he scored his first goal quickly, and he [continued] ever since and never stopped. Hopefully it will continue."

United lead City by a point as Sir Alex Ferguson's side host West Ham United on Wednesday evening, with their 32 league goals seven more than Roberto Mancini's side, and the best in the division.

Van Persie has scored eight of these while also being a creative force. Asked if the Dutchman can be the difference in the title race, Van Nistelrooy said: "I think, as he's proving right now he is making the difference on many occasions. If he can continue like this for the whole season I can see United going for another league win. Its great to see the way he plays – it fits into United's playing style. He's everywhere – he's involved in the play, and also in the finishing, so that makes him special."

Van Nistelrooy also enjoyed instant success when he joined United in the summer of 2001, and he added: "Its important for a striker when you come to a new club to get your goals and then you take it from there. He had the same. He had the experience in the Premiership already and he's proved he's a great signing."

Wayne Rooney has identified West Ham's Andy Carroll as a threat at Old Trafford on Wednesday. Carroll, who is on loan from Liverpool, scored his first goal for West Ham in Sunday's 3-1 defeat at Tottenham Hotspur. Rooney, who plays with Carroll for England, told the Manchester United website: "Andy Carroll is a handful. I am sure if you ask any defender, they find it difficult to play against someone like that who is good in the air and on the floor. He is physical and he makes it difficult. That type of player doesn't always get all the goals but they can cause trouble up front and create problems. I am sure that is what Sam Allardyce [the West Ham manager] wants him to do."

City's draw at Chelsea on Sunday meant United's two main title rivals dropped points, and Rooney added: "We know City and Chelsea will be looking out for our results as we look out for theirs. But it is important for us to concentrate on our own performances and make sure we get the wins because there are a lot of games coming up. It is tough. I am sure the manager will use his squad. It will have to come through for him."

Anderson is sure to start against West Ham, following an impressive cameo as a substitute in Saturday's 3-1 over Queens Park Rangers, according to Ferguson. "His performance was outstanding," he said. "He took the game by the scruff of the neck and he was so positive and determined in his play that he picks himself on Wednesday."

While Paul Scholes is suspended, Antonio Valencia's hip problem makes him a doubt. "We'll see what Antonio is like today and tomorrow," Ferguson said. "Nani is still going to be out [but] Chris Smalling and Phil Jones were on the bench on Saturday and they're available."