Man Utd boss Moyes: I wouldn't want to face Van Persie-Rooney combo
"If you are up against that partnership in the Premier League, you have a concern," says Moyes.
"There are some good centre-forwards in the League, but seeing Robin and Wayne up front gives defences a different dilemma. In form, they make it difficult to play against.
"I can tell the two of them are working on it. We want to try to make it a partnership where people say: "My goodness, this is tough to play against." If we can get them both scoring 20 goals this season, it will go a long way to deciding where we finish."