Manchester United manager Sir Alex Ferguson has challenged Wayne Rooney to score in every game until the end of the season.

Rooney has scored 21 goals in 26 league games so far this term, and Ferguson believes that a goal a game from now on would help the Red Devils claim a 20th league title.

"Wayne has scored something like 17 out of 17. He can keep averaging a goal a game - eight more goals - we could reasonably expect that," said the veteran manager.

"Goals are definitely going to be a factor in the championship. We've had 18 goalscorers this season which is good. Berbatov has nine, Welbeck 10 and Chicharito 12.

"Usually, we have had one outstanding scorer - Cristiano Ronaldo or Rooney. Last year, the sensation was Chicharito."

United currently sit two points clear at the top of the Premier League, a gap they could extend to five with a win over Blackburn on Monday night.