Maradona sees hope for United in the shape of Mexican star Javier Hernandez, whose performances this season have been followed in South America.
"For me, the United players who are most important are the strikers," said Maradona. "I watched Hernandez play in Mexico and you could see he was a real talent who could score goals at the best level.
"It's no surprise that he has done so well so quickly. He is a natural striker.
'But his movement and the way he plays like a ghost is perhaps the most important thing.
"Defenders don't know how to play against him because they don't even know where he is.
"Because Hernandez is a handful, Rooney gets space and time to play which creates problems."